Force & Motion Quiz For 8th Grade

Inertia is not a force itself; it's a property of matter. It describes an object's resistance to changes in its state of motion. While it's true that inertia causes objects to continue moving in a straight line at a constant speed unless acted upon by a force (Newton's first law), inertia itself doesn't "keep" them moving. It simply describes their tendency to maintain their current state of motion.

A force is indeed a push or a pull. It is a physical interaction between two objects that can cause a change in the motion or shape of an object. A force can be exerted by any object on another object and can be measured in units such as newtons. Therefore, the statement "A force is a push or a pull" is true.

The location of an object refers to its position in space. It describes where the object is located relative to a reference point or coordinate system. Therefore, the correct answer is "position".

Motion is defined as the change in position of an object relative to a reference point. This means that when an object moves from one place to another, it is considered to be in motion. The reference point is a fixed point that helps us determine the change in position. Therefore, the correct answer is "When an object changes position relative to a reference point."

Acceleration refers to the rate at which an object's velocity changes over time. It can be either positive or negative, depending on whether the object is speeding up or slowing down. Therefore, acceleration can refer to both increasing speed and decreasing speed. Additionally, acceleration also involves changing direction, as an object can accelerate even if its speed remains constant, as long as its direction changes. Therefore, the correct answer is decreasing speed, changing direction, increasing speed.

Gravity is the force of attraction that exists between any two masses, any two bodies, any two particles. It is the force that pulls objects towards each other. This force is responsible for keeping the planets in orbit around the sun, for keeping the moon in orbit around the Earth, and for bringing objects down to the ground when they are dropped. Therefore, it is correct to say that gravity is the force of attraction between all masses.

The definition of speed is the distance traveled by an object for a unit of time. Speed is a measure of how quickly an object moves, and it is calculated by dividing the distance traveled by the time it takes to travel that distance. This definition is consistent with the scientific understanding of speed and is widely accepted in the field of physics.

To determine speed, both time and distance are necessary. Time represents the duration it takes to cover a certain distance, while distance represents the length or extent of the path traveled. Without knowing either time or distance, it is impossible to calculate speed accurately. Therefore, both A (time) and B (distance) are required to determine speed.

The speed of an object at rest is 0 km/h. When an object is at rest, it is not moving and therefore has no speed. Speed is defined as the distance traveled per unit of time, and if the object is not moving, it covers no distance and has a speed of 0 km/h.

The possible units for acceleration are m/s/s (meters per second squared) and k/h/h (kilometers per hour squared). These units represent the change in velocity per unit of time, with m/s/s being the standard unit in the International System of Units (SI) and k/h/h being a less commonly used unit. The units meters and feet are units of length, while Newton is a unit of force and not directly related to acceleration.

Motion refers to the change in position of an object over time. It involves the movement of an object from one place to another. This can be in any direction and at any speed. Therefore, motion is the most appropriate term to describe the change of position of an object.

The basic unit for distance or length is meters. Meters are commonly used in the metric system and are a standard unit of measurement for length. They are used in many scientific and everyday applications worldwide.

Acceleration is the rate at which an object's velocity changes over time. It can be caused by increasing or decreasing speed, or by changing direction. Therefore, the correct answer is that acceleration can involve increasing speed, decreasing speed, or changing direction.

Adding a rough surface increases friction because it creates more contact points between the surfaces, resulting in greater resistance to motion. On the other hand, adding lubricant decreases friction by creating a thin layer between the surfaces, reducing the contact points and allowing for smoother movement. This explanation is based on the understanding that friction is the force that opposes motion between two surfaces in contact.

The word "given" is used to indicate that the direction of velocity is already specified or known. It implies that the direction is provided or mentioned in the context or problem statement. Therefore, the correct answer is "given".

Unbalanced forces occur when the forces acting on an object do not cancel each other out and result in a net force that is greater than zero. This means that there is an overall force acting on the object, causing it to accelerate or change its motion. In contrast, balanced forces occur when the forces on an object are equal in magnitude and opposite in direction, resulting in a net force of zero. Therefore, the correct answer is when the forces of an object produce a net force larger than zero.

The formula for speed is determined by dividing the distance traveled by the time taken. This formula is derived from the basic concept that speed is the rate at which an object covers distance over a specific period of time. By dividing the distance by the time, we can calculate the average speed at which an object is moving. Therefore, the correct formula for speed is speed = distance divided by time.

Even when the ball reaches its highest point and momentarily stops before falling back down, the acceleration due to gravity is still acting upon it. Gravity always acts downwards, pulling the ball towards the Earth. This constant downward acceleration causes the ball to change its direction of motion from upwards to downwards at the highest point.

The distance traveled by an object divided by the time it takes to travel that distance gives the average speed. Average velocity is the displacement divided by the time, while average acceleration is the change in velocity divided by the time. "Activity" is not a relevant term in this context. Therefore, the correct answer is average speed.

Newton's second law states that an object's acceleration depends on the mass of the object and the amount of force being applied. This means that the greater the force applied to an object, the greater its acceleration will be. Additionally, the more massive an object is, the less it will accelerate for a given force. This law helps explain the relationship between force, mass, and acceleration, and is a fundamental principle in physics.

Newton's first law states that an object in motion will stay in motion, and an object at rest will stay at rest, unless acted upon by an external force. This is also known as the law of inertia. It means that an object will continue its state of motion or rest until something causes it to change. This law explains why objects continue to move or stay still unless a force is applied to them, and it is the foundation for understanding the behavior of objects in the absence of external forces.

This is an example of Newton's First Law of Motion, also known as the law of inertia. According to this law, an object at rest will stay at rest until acted upon by an external force. In this case, the bowling pins remain at rest until the bowling ball hits them and exerts a force on them.

The correct answer is "They don't change in motion. They are equal in size. The forces are opposite in direction." This answer is correct because balanced forces do not cause a change in motion, meaning that an object will continue to move at a constant velocity or remain at rest. Balanced forces are also equal in size, meaning that the magnitudes of the forces are the same. Additionally, the forces are opposite in direction, which means that they act in opposite directions on the object. These characteristics of balanced forces ensure that there is no net force acting on an object, resulting in a balanced state.

This scenario is an example of Newton's Third Law of Motion, which states that for every action, there is an equal and opposite reaction. The first skater pulling upward on the second skater creates a force, and in response, the second skater pulls downward on the first skater with an equal force. These two forces are equal in magnitude but opposite in direction, demonstrating the principle of action and reaction.

Inertia is not a property of matter. It is a property of objects that describes their resistance to changes in motion. Inertia is dependent on mass, not matter itself.

A reference point is the object that stays in place. It is used as a fixed point to measure the position or motion of other objects. By observing how other objects change position relative to the reference point, we can determine their motion or displacement.

The passenger in the rear seat of a car moving at a steady speed is at rest relative to the front seat of the car because both the passenger and the front seat are moving at the same speed and in the same direction. The passenger is not at rest relative to the side of the road, the pedestrian on the corner ahead, or the wheels of the car, as they are all moving relative to the passenger.

When you push or pull an object, the mass of the object remains constant. However, the force applied to the object causes it to accelerate. This means that the object's velocity changes over time. Therefore, the correct answer is acceleration.

The slope of a line on a distance-time graph represents the rate at which an object is moving. In this case, the correct answer is "Speed" because speed is defined as the distance traveled per unit of time. The slope of the line on a distance-time graph gives the speed of the object, indicating how fast or slow it is moving.

Balanced forces occur when the forces acting on an object are equal in magnitude and opposite in direction, resulting in a net force of zero. This means that the object will remain at rest if it was initially at rest, or it will continue to move at a constant velocity if it was already in motion. In other words, the forces are balanced and cancel each other out, leading to no change in the object's motion.

The explanation for the correct answer "Both A and B" is that the statement is comparing the speed of motion with the steepness of the incline or slope. It suggests that as the motion becomes faster, the incline or slope becomes steeper. This implies a direct relationship between the speed of motion and the steepness of the incline or slope. Therefore, both options A (incline) and B (slope) are correct.

This question is asking for the law of motion that explains the change in motion of a volleyball when an unbalanced force acts on it. Newton's First Law of Motion 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 unbalanced force. Therefore, this example does not fit Newton's First Law. Newton's Third Law of Motion states that for every action, there is an equal and opposite reaction. This law does not directly explain the change in motion of the volleyball. Newton's Second Law of Motion states that the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass. This law explains the change in motion of the volleyball due to the unbalanced force, so the correct answer is Newton's Second Law of Motion.

The measure of an object's position during a unit of time is called speed. Speed is a scalar quantity that represents the rate at which an object moves. It is calculated by dividing the distance traveled by the time taken. Unlike velocity, which includes both the speed and direction of an object's motion, speed only focuses on the magnitude of the motion. Acceleration refers to the rate of change of velocity, while momentum is the product of an object's mass and velocity.

Instantaneous speed is a measure of an object's speed at a specific moment in time. It is not measured at the starting point or when the object reaches its destination, as these would be average speeds over a period of time. Instead, instantaneous speed is measured at a particular instant, providing a snapshot of the object's speed at that exact moment.

When the only force acting on an object is gravity, the object is said to be in free fall. In free fall, the object is accelerating downwards solely due to the force of gravity, with no other forces counteracting it. This means that the object is not supported by any surface or experiencing any other forces that would oppose its motion. Free fall is commonly observed when objects are dropped from a height or when a person jumps out of an airplane without a parachute.