1.
1. Speed is
Correct Answer
A. Distance divided by time
Explanation
Speed is a measure of how fast an object is moving. It is calculated by dividing the distance traveled by an object by the time it takes to travel that distance. This formula, distance divided by time, allows us to quantify the rate at which an object is moving and compare it to other objects or situations. Therefore, the correct answer is "distance divided by time".
2.
2. Velocity is speed and _________________
Correct Answer
C. Direction
Explanation
Velocity is defined as the rate at which an object changes its position in a specific direction. While speed only indicates how fast an object is moving, velocity includes both speed and direction. Therefore, velocity is not only dependent on the magnitude of the speed but also on the direction in which the object is moving.
3.
3. When tracking or providing information about a tornado, which is most important to know?
Correct Answer
C. Velocity
Explanation
When tracking or providing information about a tornado, velocity is the most important factor to know. Velocity refers to the speed and direction of the tornado's movement, which is crucial for predicting its path and potential impact. While speed and time are also relevant, velocity combines both of these factors and provides a more comprehensive understanding of the tornado's behavior. By knowing the velocity, meteorologists and emergency responders can better assess the potential danger and issue timely warnings to affected areas.
4.
4. Acceleration is the rate at which ______________ changes.
Correct Answer
A. Velocity
Explanation
Acceleration is the rate at which velocity changes. Velocity is a vector quantity that includes both speed and direction. Therefore, acceleration measures how quickly an object's speed and/or direction changes over time.
5.
5. If a tornado is moving at 50 mph in a NE direction, what is its velocity?
Correct Answer
B. 50 mph NE
Explanation
The correct answer is 50 mph NE because velocity is a vector quantity that includes both speed and direction. In this case, the tornado is moving at a speed of 50 mph and its direction is northeast. Therefore, the velocity of the tornado is 50 mph in the northeast direction.
6.
6. One way you can write speed is
Correct Answer
C. Both
Explanation
The correct answer is both because "55 m/h" and "55 mph" are both valid ways to express speed. "m/h" stands for meters per hour, while "mph" stands for miles per hour. Both units can be used to measure the speed of an object or vehicle.
7.
The surface of any object is rough.
Correct Answer
A. False
Explanation
The statement "the surface of any object is rough" is false. This is because not all objects have rough surfaces. Some objects can have smooth surfaces, such as a glass table or a polished marble floor. The roughness or smoothness of an object's surface depends on various factors like the material it is made of, the manufacturing process, and the intended purpose of the object.
8.
8. Kinetic friction is
Correct Answer
A. Unbalanced or moving
Explanation
Kinetic friction refers to the force that opposes the relative motion between two surfaces in contact. It occurs when there is relative motion or movement between the objects. Therefore, the correct answer "unbalanced or moving" accurately describes kinetic friction as it is present when there is motion or movement between the surfaces in contact.
9.
9. Balanced friction is
Correct Answer
B. Static
Explanation
Balanced friction refers to the situation where the force of friction acting on an object is equal to the applied force, resulting in the object being at rest and not moving. In this case, the correct answer is "static" because it accurately describes the state of balanced friction where there is no relative motion between the object and its surroundings.
10.
10. Friction is helpful when
Correct Answer
A. You are sliding on ice and want to stop.
Explanation
Friction is helpful when you are sliding on ice and want to stop because it creates a force that opposes the motion, allowing you to slow down and eventually come to a stop. On ice, there is very little friction, so it is necessary to create additional friction by applying force in the opposite direction to counteract the sliding motion. This is why friction is helpful in this situation.
11.
11. When you roll a ball, you know it will stop, why?
Correct Answer
D. All of the above
Explanation
The correct answer is "all of the above." When you roll a ball, it will eventually stop because of an unbalanced force acting on it. Friction between the ball and the surface it is rolling on will cause it to slow down and eventually come to a stop. Additionally, if the ball and the surface have rough textures, they will create more friction when rubbing against each other, further contributing to the ball's eventual stop.
12.
12. Why does a door squeak when you open/close it?
Correct Answer
B. Too much friction
Explanation
When a door squeaks when you open or close it, it is because there is too much friction between the moving parts of the door. Friction is the force that opposes motion between two surfaces in contact, and when there is excessive friction, it can cause the door to make a squeaking sound. This can occur when the hinges or other components of the door are not properly lubricated or when there is dirt or debris present, causing increased resistance and noise when the door is moved.
13.
13. To get grime and food off a pan, you
Correct Answer
B. Add more pressure to the friction
Explanation
Adding more pressure to the friction helps to remove grime and food off a pan because it increases the force applied between the pan and the sponge. This increased force enhances the friction between the two surfaces, allowing for better scrubbing and more effective cleaning.
14.
14. Gravity pulls matter toward Earth's surface, true or false
Correct Answer
B. True
Explanation
Gravity is a force that attracts objects towards each other. On Earth, gravity pulls all matter, including humans and objects, towards its surface. This is why we stay grounded and objects fall when dropped. Therefore, the statement that gravity pulls matter toward Earth's surface is true.
15.
15. Gravity is the force of attraction between
Correct Answer
C. Two objects
Explanation
Gravity is the force of attraction between two objects. This is because every object with mass exerts a gravitational force on every other object with mass. The strength of this force depends on the mass of the objects and the distance between them. Therefore, gravity can only exist between two objects and not more.
16.
16. As mass increases, gravity's pull increases. This is called
Correct Answer
B. The law of universal gravitation
Explanation
The law of universal gravitation states that the force of gravity between two objects is directly proportional to their masses and inversely proportional to the square of the distance between them. As mass increases, the force of gravity also increases, according to this law. Therefore, the given statement aligns with the law of universal gravitation.
17.
17. Mass is a measure of
Correct Answer
B. Matter
Explanation
Mass is a measure of matter. It refers to the amount of substance an object contains and is a fundamental property of matter. Mass is independent of gravity and remains the same regardless of the location of the object. It is commonly measured in units such as kilograms or grams.
18.
18. Weight is a measure of
Correct Answer
A. Gravity's force on an object
Explanation
Weight is a measure of gravity's force on an object. When an object is in a gravitational field, it experiences a force due to gravity. This force is what we commonly refer to as weight. Weight is directly proportional to the mass of an object and the strength of the gravitational field it is in. Therefore, weight can be considered as a measure of the gravitational force acting on an object.
19.
19. The ___________ is the unit of force.
Correct Answer
C. Newton
Explanation
The unit of force is called the newton. It is named after Sir Isaac Newton, a physicist who made significant contributions to the field of mechanics and formulated the laws of motion. The newton is defined as the amount of force required to accelerate a one-kilogram mass by one meter per second squared. It is the standard unit of force in the International System of Units (SI).
20.
20. When observing motion, the object that appears to stay in place is called the
Correct Answer
C. Reference point
Explanation
A reference point is an object or location that is used to compare the motion of other objects. It appears to stay in place while other objects move relative to it. In the context of observing motion, a reference point is used to determine if an object is moving or not. It provides a frame of reference for measuring and describing the motion of other objects. Therefore, the correct answer is reference point.