Newton's Laws of Motion

A meteor moving 468 km per minute traveling in a south-to-north direction passed near Earth in 2013. Because the meteor was only 45 m wide and was 27,700 km above Earth's surface, it was not visible without the aid of a telescope. Which statement describes the meteor's motion?

• Its velocity was 7.8 km/s northward.

• Its acceleration was 468 km/s².

• Its speed was 468 km/s northward.

• Its acceleration was 7.8 km/s².

A student graphed the position of a cart during a 7-second time interval. Which statement best describes the cart?

• The cart was stationary with a velocity of 0 m/s for the entire 7 seconds.

• The cart was stationary except for a short burst of acceleration of 0.5 m/s².

• The cart moved at a constant velocity of 0.5 m/s for the entire 7 seconds.

• The cart accelerated at a constant rate of approximately 0.8 m/s².

Which of the following best describes the velocity of an object?

• 30 m/s

• 30 m east

• 30 m/s east

• 30 m/s²

What is the difference between the velocity and the speed of an object?

• Velocity is the change in distance over time, while speed is the change in velocity over time.

• Velocity has a direction associated with it, while speed has no specific direction.

• Velocity has no direction associated with it, while speed has a specific direction.

• Velocity is the change in speed over time, while speed is the change in velocity over time.

The three vehicles shown below are all traveling at a speed of 15 m/s, but only the pickup truck has a changing velocity. The pickup truck has a changing velocity because the pickup truck -

• can accelerate faster than the other two vehicles

• is traveling in the opposite direction from the other two vehicles

• is traveling on a curve in the road

• needs a large amount of force to move

The picture shows an aerialist walking on a tightrope and holding a balancing bar. An action-reaction pair of forces exists between -

• the aerialist's feet and the rope

• the rope and the balancing bar

• the two ends of the rope

• the aerialist's arms and legs

Four boxes are sliding with constant speed before each box experiences an unbalanced force of 8 N. Which box would experience the greatest acceleration when the unbalanced force is applied?

• The box with a mass of 2 kg

• The box with a mass of 4 kg

• The box with a mass of 6 kg

• The box with a mass of 8 kg

The unusual strength of a glue makes it able to hold a heavy object, or load, as shown in the diagram below. If the load exerts a strong downward force, the glue -

• destroys the force

• exerts a stronger downward force

• causes the load to accelerate upward

• exerts an upward force that is equal to the downward force

Two forces applied to a 17 kg box, as shown. The box is on a smooth surface. Which statement best describes the acceleration of the box?

• The box accelerates at 1.0 m/s² to the right because the net force is 17 N to the right.

• The box accelerates at 1.9 m/s² to the right because the greater the force is to the right.

• The box accelerates at 3.0 m/s² to the combined forces cause the box to accelerate.

• The box does not accelerate, because neither force is large enough to move the box.

The list includes six situations. Which objects in the list experience an unbalanced force?

• The book, the ball, and the car

• The ball, the car, and the bird

• The can, the swing, and the bird

• The book, the ball, the can, and the swing