Work & energy worksheet with answers

Free printable Work & energy worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
m = 5 kggh = 47 m

A 5 kg ball is dropped from rest from a height of 47 m. Ignore air resistance. Find its kinetic energy Ek just before it hits the ground.

m = 5 kgh = 47 mg = 9.81 m/s²
Ek = J
2.Easy
m = 2 kggh = 12 m

A 2 kg ball is dropped from rest from a height of 12 m. Ignore air resistance. Find its speed v just before it hits the ground.

m = 2 kgh = 12 mg = 9.81 m/s²
v = m/s
3.Medium
0.2 kgk = 2000 N/mh = ?

A toy launcher has a vertical spring of stiffness 2000 N/m. A 0.2 kg ball is placed on it and the spring is compressed by 2 cm, then released. Ignoring air resistance and the spring’s mass, find the height h the ball rises, measured from its position when the spring was compressed.

m = 0.2 kgk = 2000 N/mx = 2 cmg = 9.81 m/s²
h = m
4.Medium
40°d = 18 mμ = 0.15

A 5 kg block slides 18 m down a slope at 40° to the horizontal, with a coefficient of kinetic friction of 0.15. Find the work Wf done against friction.

m = 5 kgθ = 40°μ = 0.15d = 18 mg = 9.81 m/s²
Wf = J
5.Hard
h = 3.5 mL = 2.5 mμ = 0.3k = 2500 N/m

A 2.5 kg block is released from rest at height 3.5 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 2.5 m long (μ = 0.3) and then runs onto a spring (k = 2500 N/m) on a smooth surface. Find the maximum compression x of the spring.

m = 2.5 kgh = 3.5 mL = 2.5 mμ = 0.3k = 2500 N/mg = 9.81 m/s²
x = cm
6.Hard
2 kg6 kgμ = 0.15d = 0.5 m

A 2 kg block rests on a rough horizontal table (μ = 0.15). A light string runs from it over a smooth pulley at the edge of the table to a hanging 6 kg block. The system is released from rest. Find the speed v of the blocks after the hanging block has dropped 0.5 m.

m1 = 2 kgm2 = 6 kgμ = 0.15d = 0.5 mg = 9.81 m/s²
v = m/s

Answer key

  1. 1. Ek = 2305 J
  2. 2. v = 15.34 m/s
  3. 3. h = 0.2039 m
  4. 4. Wf = 101.5 J
  5. 5. x = 23.23 cm
  6. 6. v = 2.644 m/s

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