⚡ Energy — Unit Quiz

A force of 50 N is applied to a box in the direction of motion, moving it 4 m. How much work does the force do?

A 3 kg object is moving at 4 m/s. What is its kinetic energy?

A 2 kg book is held 5 m above the floor. What is its gravitational potential energy relative to the floor? (g = 10 m/s²)

A machine does 600 J of work in 30 seconds. What is its power output?

A ball rolls off a table and falls to the floor. Ignoring air resistance, select ALL forms of energy the ball has just before it hits the floor.

A 2 kg box is pushed 5 m by a 10 N force perpendicular to the motion. How much work does the force do?

A ball is dropped from rest at height h. Using energy conservation, what is its speed just before hitting the ground?

A 4 kg box moving at 6 m/s is brought to a stop by friction over a distance of 3 m. What is the magnitude of the friction force?

Select ALL situations where mechanical energy (KE + PE) is conserved.

A spring with k = 400 N/m is compressed by 0.05 m. How much elastic potential energy is stored in the spring?

A 2 kg block is released from rest at the top of a curved frictionless ramp 5 m above the ground. At the bottom, it encounters a rough horizontal surface and travels 4 m before stopping. What is the coefficient of kinetic friction on the horizontal surface? (g = 10 m/s²)

A 500 kg elevator (motor power = 10,000 W) rises at constant velocity. What is the maximum constant speed the elevator can rise? (g = 10 m/s²)

A 1 kg ball is thrown upward at 10 m/s from the ground. Ignoring air resistance. Select ALL correct statements at the moment the ball is halfway to its maximum height. (g = 10 m/s²)

A 5 kg block slides from rest down a 3 m ramp inclined at 37° with μ_k = 0.2. (a) Find the speed at the bottom using energy methods. (b) How does your answer change if the mass is doubled to 10 kg? Explain conceptually. (g = 10 m/s², sin 37° = 0.6, cos 37° = 0.8)

A 400 g ball is launched from a spring-loaded cannon. The spring has k = 800 N/m and is compressed 0.15 m. The ball rises to a maximum height H above the cannon. (a) Find the total energy stored in the spring. (b) Find the maximum height H the ball reaches, assuming no energy losses. (g = 10 m/s²)