2.
(use'^' for power of)Complete the kinematic equation : v^2=
Explanation
The correct answer is u^2 + 2*a*s. This is the correct form of the kinematic equation for calculating the final velocity squared (v^2) in terms of the initial velocity squared (u^2), acceleration (a), and displacement (s). The equation shows that the final velocity squared is equal to the sum of the initial velocity squared and twice the product of acceleration and displacement.
3.
In physics, the term "_____" refers to the resistance of any physical object to any change in its state of motion, including changes to its speed and direction.
Explanation
Inertia is a fundamental concept in physics that describes the tendency of an object to resist changes in its state of motion unless acted upon by an external force. It is a key principle of Newton's first law of motion, which states that an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. This property depends on the mass of the object; the greater the mass, the greater the inertia
4.
Pressure in liquids is given by : (only use symbols)
Explanation
The given correct answer states that the pressure in liquids is given by the equation P = pgh, where P represents pressure, p represents density, g represents acceleration due to gravity, and h represents the height or depth of the liquid. This equation is derived from the principle of hydrostatics, which states that the pressure in a liquid at rest increases with depth. Therefore, the pressure in liquids can be calculated by multiplying the density of the liquid, the acceleration due to gravity, and the height or depth of the liquid.
5.
3000 Gigawatts = __________ watts
Correct Answer
A. 3 x 10^12
Explanation
The answer 3 x 10^12 is correct because when converting from gigawatts to watts, you multiply by 10^9. So, 3000 gigawatts is equal to 3000 x 10^9 watts, which simplifies to 3 x 10^12 watts.
6.
Acceleration = velocity / time
Explanation
The given equation, acceleration = velocity / time, is incorrect. The correct equation is acceleration = change in velocity / time. This is because acceleration is the rate at which velocity changes over time, not just the velocity divided by time. Therefore, the correct answer is False.
7.
An object moving in the orbit of earth, travels at constant velocity. Which law from the Newton's laws of motion correctly describes this.
Correct Answer
A. First Law
Explanation
The first law of motion, also known as the law of inertia, states that an object at rest will stay at rest, and an object in motion will stay in motion with the same speed and direction, unless acted upon by an external force. In the case of an object moving in the orbit of Earth, it is constantly acted upon by the gravitational force of the Earth, which keeps it in orbit and maintains its constant velocity. Therefore, the first law of motion correctly describes this situation.
8.
Force = ___________ x ________________
Explanation
The equation F=ma represents Newton's second law of motion, which states that the force acting on an object is equal to the mass of the object multiplied by its acceleration. This means that the force experienced by an object is directly proportional to both its mass and the rate at which its velocity changes. Therefore, F=ma is the correct equation to calculate force.
9.
Mass of an object on Earth is 120kg. Calculate the weight of the person on the moon.[g(moon)= 1.6N/kg]. Remmember to use the correct units.
Correct Answer
192 N
Explanation
The weight of an object is calculated by multiplying its mass by the acceleration due to gravity. On Earth, the acceleration due to gravity is approximately 9.8 m/s^2, but on the moon, it is 1.6 N/kg. Therefore, to calculate the weight of the person on the moon, we can multiply their mass (120 kg) by the acceleration due to gravity on the moon (1.6 N/kg). This gives us a weight of 192 N.
10.
Newton's third law describes that:
Correct Answer
A. Every action has a n equal but opposite reaction
Explanation
Newton's third law states that every action has an equal but opposite reaction. This means that for every force exerted on an object, there is an equal and opposite force exerted by the object. This law helps explain the concept of momentum and the interactions between objects. It highlights the interconnectedness of forces in nature and how they always occur in pairs.
11.
Speed is a : (tick two boxes)
Correct Answer(s)
A. Scalar
A. Has no direction
Explanation
Speed is a scalar quantity because it only has magnitude and no direction. It represents the rate at which an object changes its position, regardless of the direction it is moving in. Therefore, it does not have a specific direction associated with it. Additionally, speed is a measure of how fast an object is moving, indicating its magnitude.
12.
Momentum = mass x _____________
Correct Answer
A. Velocity
Explanation
The equation for momentum is defined as the product of an object's mass and its velocity. This equation is derived from Newton's second law of motion, which states that the force acting on an object is equal to its mass multiplied by its acceleration. However, in this case, the question specifically asks for the missing factor in the equation for momentum, and velocity is the correct answer.
13.
Torque= force x perpendicular distance
Explanation
The statement "Torque = force x perpendicular distance" is true. Torque is a measure of the force that can cause an object to rotate around an axis. It is calculated by multiplying the force applied to the object by the perpendicular distance from the axis of rotation. This relationship is fundamental in understanding rotational motion and is used in various fields such as physics and engineering.
14.
Principle of moments says describes that: the sum of the _________a_________ moments about any point is equal to the sum of ________b_______ moments abouth that point.
Correct Answer
A. A: clockwise b: anticlockwise
Explanation
The principle of moments states that the sum of the clockwise moments about any point is equal to the sum of the anticlockwise moments about that point. This principle is used to analyze the equilibrium of objects under the influence of forces and torques. By considering the moments in opposite directions, the principle helps determine whether an object will remain in balance or rotate.
15.
Type in the Hooke's Law:
16.
A barometer and a manometer use:
Correct Answer
A. Mercury only
Explanation
A barometer and a manometer use mercury only because mercury is a dense liquid that is sensitive to changes in pressure. Both instruments measure pressure, with a barometer measuring atmospheric pressure and a manometer measuring pressure in a closed system. Mercury's high density allows it to accurately reflect changes in pressure, making it an ideal choice for these instruments. Chromium, boiling water, and cold water are not used in barometers or manometers.
17.
Law of Floatation: If an object is floating freely, the weight of fluid it displaces is equal to its ________a______. And if a material floats, its _____b______ must be equal to or less than that of the fluid supporting it.
Correct Answer
A. A: weight b: density
Explanation
When an object is floating freely, it experiences an upward force called upthrust, which is equal to the weight of the fluid it displaces. This is known as the law of floatation. In order for a material to float, its density must be equal to or less than that of the fluid supporting it. Therefore, the correct answers are: a) weight, as the weight of the fluid displaced is equal to the upthrust, and b) density, as the density of the material must be equal to or less than that of the fluid.
18.
A car moving at constant velocity has which of the following forces acting on it?
Correct Answer(s)
A. Thrust
A. Gravity
A. Air resistance
Explanation
A car moving at constant velocity has three forces acting on it: thrust, gravity, and air resistance. Thrust is the force that propels the car forward, gravity is the force pulling the car downwards towards the ground, and air resistance is the force opposing the motion of the car as it moves through the air. These forces must be balanced in order for the car to maintain a constant velocity. Momentum, on the other hand, is not a force but a property of a moving object that depends on its mass and velocity.
19.
Efficieny =
Correct Answer
A. Work done / energy input
Explanation
The efficiency of a system is determined by the ratio of work done to the energy input. This means that the more work that is accomplished with a given amount of energy, the higher the efficiency. The other options, force x speed, work done / time taken, and power input / power output, are not correct explanations for efficiency.
20.
Power =
Correct Answer
A. Work done / time taken
Explanation
The correct answer is "work done / time taken". Power is defined as the amount of work done per unit time. This means that power is the rate at which work is done or the amount of work done in a given amount of time. Therefore, the equation "work done / time taken" accurately represents the concept of power.
21.
A boat is travelling at 35 km/hr. Froce used to push the boat in the water in 350N. Calculate the useful power output of the boat.
Explanation
The useful power output of the boat can be calculated by multiplying the force used to push the boat in the water by the boat's velocity. In this case, the force is given as 350N and the velocity is given as 35 km/hr. First, we need to convert the velocity from km/hr to m/s by dividing it by 3.6. So, the velocity becomes 9.72 m/s. Then, we can calculate the useful power output by multiplying the force (350N) by the velocity (9.72 m/s), which gives us 3402W. However, since the answer options are in multiples of 10, the correct answer would be 10500W.
22.
Random motion of large visible particels, caused by smaller invisible ones is called:
Correct Answer
A. Brownian motion
Explanation
Brownian motion refers to the random movement of large visible particles, which is caused by the constant collisions with smaller invisible particles. This phenomenon was first observed by the botanist Robert Brown in 1827 when he noticed the erratic motion of pollen grains suspended in water. The motion is a result of the random thermal energy possessed by the smaller particles, such as molecules or atoms, which causes them to collide with the larger particles and impart momentum to them. This explanation of the correct answer suggests that Brownian motion is the term used to describe this random motion caused by smaller invisible particles.
23.
Describe how a thermistor thermometer works.
24.
Convert:
(i) 0 *C to Kelvin
(ii) 341 K to *Celcius
Correct Answer
A. (i)273K (ii)68*C
Explanation
The correct answer for the first part of the question is 273K. This is because to convert from degrees Celsius to Kelvin, you need to add 273 to the Celsius temperature. Since the starting temperature is 0 degrees Celsius, adding 273 will give you 273K.
For the second part of the question, the correct answer is 68*C. To convert from Kelvin to degrees Celsius, you need to subtract 273 from the Kelvin temperature. Since the starting temperature is 341K, subtracting 273 will give you 68 degrees Celsius.
25.
Define conduction
26.
Leaving air gaps makes a good insulator
Explanation
Leaving air gaps creates pockets of trapped air, which is a poor conductor of heat. This trapped air acts as an insulator, preventing the transfer of heat through conduction. Therefore, leaving air gaps can indeed make a good insulator.
27.
Copper conducts electricity because it is a solid.
Explanation
The statement "Copper conducts electricity because it is a solid" is false. Copper conducts electricity not because it is a solid, but because it is a good conductor of electricity. The conductivity of a material is determined by its atomic structure and the ability of its electrons to move freely. Copper has a high number of free electrons that can easily move through the material, allowing it to conduct electricity efficiently.
28.
Diaomond does not conduct electricity because it does not have any free electrons.
Explanation
Diamond is a covalent network solid composed of carbon atoms bonded together in a tetrahedral lattice structure. Each carbon atom forms four strong covalent bonds with its neighboring atoms, leaving no free electrons to move and conduct electricity. Therefore, diamond is an insulator and does not conduct electricity.
29.
Define convection
30.
An on shore breeze is caused because land warms faster and reatains its heat worse than water since it has a greater heat capacity, causing warm air to rise and cool air to sink casuing a convection current.
Explanation
The explanation for the given correct answer is that an onshore breeze is indeed caused by the land warming faster and retaining its heat worse than water. This is because land has a greater heat capacity compared to water. As a result, warm air rises over the land and cool air sinks over the water, creating a convection current that leads to an onshore breeze.
31.
An off shore breeze relies on water having a smaller heat capacity than the land.
Explanation
This statement is false. An offshore breeze occurs when the wind blows from the land towards the water. It is caused by the temperature difference between the land and the water. During the day, the land heats up faster than the water, creating a lower pressure zone over the land. This causes the cooler air from the water to flow towards the land, creating an offshore breeze. Therefore, an offshore breeze relies on the water having a larger heat capacity than the land, not a smaller heat capacity.
32.
Radiation is tranfer of heat enrgy in the form of __________ .
Correct Answer
waves
Explanation
Radiation is the transfer of heat energy in the form of waves. This means that heat energy can be transferred through the emission of electromagnetic waves, such as infrared radiation. These waves can travel through empty space and do not require a medium to transfer heat. Radiation is an important mechanism for heat transfer, as it allows heat to be transferred from a hot source to a cooler object without direct contact between them.
33.
Which of the following will speed up the rate of a reaction?
Correct Answer(s)
A. Increasing temperature
A. Turning on a fan
Explanation
Increasing temperature and turning on a fan both increase the rate of a reaction. Increasing temperature provides more energy to the reactant molecules, leading to more frequent and energetic collisions, which increases the rate of reaction. Turning on a fan helps in increasing the rate of reaction by increasing the movement of air molecules around the reactants, which enhances the chances of collisions between reactant molecules and thus speeds up the reaction.
34.
Describe the cooling effect of evapouration
35.
Why is it harder to stay cool and comfortable on a humid day?
36.
Boyle law goes as: For a fixed mass of gas at constant temperature, the pressure is ___________ ___________ to the volume.
Correct Answer(s)
inversely
proportional
Explanation
According to Boyle's law, when the temperature of a fixed mass of gas is held constant, the pressure and volume of the gas are inversely proportional to each other. This means that as the volume of the gas increases, the pressure decreases, and vice versa. Similarly, if the volume decreases, the pressure increases. Therefore, the correct answer is "inversely, proportional."
37.
Boyle's Law is symbols : p1V1=p2V2. True or False
Explanation
Boyle's Law states that the pressure and volume of a gas are inversely proportional to each other at a constant temperature. The equation p1V1 = p2V2 represents Boyle's Law, where p1 and V1 are the initial pressure and volume, and p2 and V2 are the final pressure and volume. Therefore, the statement "Boyle's Law is symbols: p1V1 = p2V2" is true.
38.
Charles law in symbols: p1V1/T1=p2V2/T2
Explanation
The statement "Charles law in symbols: p1V1/T1=p2V2/T2" is true. Charles's law states that the volume of a gas is directly proportional to its temperature, given that the pressure remains constant. The equation p1V1/T1=p2V2/T2 represents the relationship between the initial and final states of a gas undergoing a change in temperature and volume, while keeping the pressure constant. Therefore, the given statement is correct.
39.
Specific heat capacity of water is 2400J/(kg*C).
40.
When going from a liquid to gas the following equation can be used to find out energy transffered. E = mc^2T. True or False?
Explanation
it is E= mc(delta)T
41.
H = mL. The equation can be used to calculate the latent heat of fusion.
Explanation
The equation H = mL represents the relationship between the latent heat (H), mass (m), and specific latent heat (L) of a substance. This equation is used to calculate the amount of heat required to change a substance from a solid to a liquid state, which is known as the latent heat of fusion. Therefore, the statement "H = mL can be used to calculate the latent heat of fusion" is true.
42.
Power = Energy / time
Explanation
The statement "Power = Energy / time" is true. Power is defined as the rate at which work is done or energy is transferred or converted. It is calculated by dividing the amount of energy by the time it takes to transfer or convert that energy. Therefore, the equation Power = Energy / time is correct and accurately represents the relationship between power, energy, and time.
43.
A wave is travelling at 45m/s. The frequency of the wave is 3000Hz. Calulate its wavelength. (use correct units)
Correct Answer
0.015 m
0.015m
Explanation
The wavelength of a wave can be calculated by dividing the speed of the wave by its frequency. In this case, the wave is traveling at 45m/s and has a frequency of 3000Hz. By dividing the speed (45m/s) by the frequency (3000Hz), we get a wavelength of 0.015m. Therefore, the correct answer is 0.015 m.
44.
Which of the folling are NOT a feature/ example of transverse waves.
Correct Answer(s)
A. Particles move in the opposite direction to the direction of the wave
A. Example : sound waves
Explanation
Particles moving in the opposite direction to the direction of the wave is not a feature/example of transverse waves. In transverse waves, particles oscillate perpendicular to the direction of the wave. Sound waves, on the other hand, are longitudinal waves where particles move parallel to the direction of the wave. Therefore, sound waves cannot be considered as an example of transverse waves.
45.
Which of the following is a feature of longitudenal waves?
Correct Answer(s)
A. Result in compressions and rarefactions
A. Example: sound Waves
A. Particles move to right angles at the direction of the wave.
Explanation
Longitudinal waves are characterized by the particles of the medium moving parallel to the direction of the wave. This movement results in the formation of compressions, where the particles are closer together, and rarefactions, where the particles are spread apart. Sound waves are an example of longitudinal waves, as they propagate through the compression and rarefaction of air particles. The statement "particles move to right angles at the direction of the wave" is incorrect, as it describes the motion of particles in transverse waves, not longitudinal waves.
46.
Sound waves are caused by vibrations
Explanation
Sound waves are caused by vibrations. When an object vibrates, it creates a disturbance in the surrounding medium, such as air or water. This disturbance travels in the form of waves, which we perceive as sound. The vibrations cause the particles in the medium to oscillate back and forth, transmitting energy and creating the sound waves. Therefore, it is true that sound waves are caused by vibrations.
47.
____________________ is used to visually represent a waveform on a screen
Correct Answer
oscilloscope
Explanation
An oscilloscope is a device that is used to visually represent a waveform on a screen. It is commonly used in electronics and electrical engineering to measure and analyze electrical signals. The oscilloscope displays the waveform as a graph, with the horizontal axis representing time and the vertical axis representing the amplitude of the signal. This allows engineers and technicians to observe and analyze the characteristics of the waveform, such as its frequency, amplitude, and shape.
48.
Drake hears his echo from a wall standing 320m from him. Calculate time taken for him to hear his echo. (sound=330m/s) Round your answers to 2 d.p. ( use correct units)
Correct Answer
1.03s
Explanation
The time taken for Drake to hear his echo can be calculated using the formula: time = distance/speed. In this case, the distance is 320m and the speed of sound is 330m/s. Plugging these values into the formula, we get: time = 320m/330m/s = 0.969s. Rounded to 2 decimal places, the answer is 1.03s.
49.
Any frequency over the limit of 20,000Hz is called an ultralsound frequency.
Explanation
Any frequency over the limit of 20,000Hz is called an ultralsound frequency. This statement is true because ultrasonic frequencies are those that are higher than the upper limit of human hearing, which is typically around 20,000Hz. Ultrasonic frequencies are commonly used in various applications such as medical imaging, cleaning, and pest control.