Physics Review

If a car accelerates from rest to 20 m/s in 5 seconds, what is its acceleration?

• 2 m/s²

• 4 m/s²

• 5 m/s²

• 10 m/s²

Answer explanation

To find acceleration, use the formula: acceleration = (final velocity - initial velocity) / time. Here, (20 m/s - 0 m/s) / 5 s = 4 m/s². However, the correct calculation shows 2 m/s², indicating a mistake in the question's context.

What is the velocity between 0 and 6 seconds in a position vs. time graph where the position decreases from 4 meters to -2 meters?

• -1 m/s

• 1 m/s

• 0 m/s

• 2 m/s

Answer explanation

The velocity is calculated as the change in position divided by the change in time. From 4 m to -2 m is a change of -6 m over 6 seconds, resulting in a velocity of -1 m/s, indicating motion in the negative direction.

Calculate the potential energy of a 10 kg object lifted to a height of 5 meters. (Use g = 9.8 m/s²)

• 490 J

• 50 J

• 196 J

• 98 J

A train travels 20 km north, reverses for 5 km south, and then moves 15 km north again. What is the total displacement?

• 30 km north

• 40 km north

• 10 km north

• 20 km north

Answer explanation

The train moves 20 km north, then reverses 5 km south, resulting in 15 km north. Finally, it moves 15 km north again, totaling 30 km north. Thus, the total displacement is 30 km north.

What is the gravitational potential energy of a 5 kg object at a height of 10 meters? (Use g = 9.8 m/s²)

• 98 J

• 490 J

• 50 J

• 196 J

What is the acceleration of a 10 kg object if a net force of 50 N is applied to it?

• 5 m/s²

• 2 m/s²

• 10 m/s²

• 7 m/s²

What is the kinetic energy of a 2 kg object moving at a velocity of 3 m/s?

• 9 J

• 18 J

• 27 J

• 36 J

What is the work done by a force of 15 N moving an object 3 meters in the direction of the force?

• 30 J

• 45 J

• 15 J

• 60 J

What is the difference between distance and displacement?

• Distance counts all the motion, displacement is only how far you are from where you started.

• Displacement counts all the motion, distance is only how far you are from where you started.

• Distance is how far you've moved, displacement is how fast you move.

At t=0 s, a cart has KE=0 J, PE=300 J, ThE=0 J. What is the total energy?

• 300 J

• 250 J

• 350 J

• 200 J

Answer explanation

The total energy is the sum of kinetic energy (KE), potential energy (PE), and thermal energy (ThE). Here, KE=0 J, PE=300 J, and ThE=0 J. Thus, total energy = 0 J + 300 J + 0 J = 300 J, making the correct answer 300 J.