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 = 10 kggh = 7 m

A 10 kg ball is dropped from rest from a height of 7 m. Ignore air resistance. Find its kinetic energy Ek just before it hits the ground.

m = 10 kgh = 7 mg = 9.81 m/s²
Ek = J
2.Easy
20°L = 0.8 m

A small ball hangs on a light string of length 0.8 m. It is pulled aside until the string makes 20° with the vertical and released from rest. Ignoring air resistance, find its speed v at the lowest point.

L = 0.8 mθ = 20°g = 9.81 m/s²
v = m/s
3.Medium
35°d = 19 mμ = 0.1

A 2 kg block slides 19 m down a slope at 35° to the horizontal, with a coefficient of kinetic friction of 0.1. Find the work Wf done against friction.

m = 2 kgθ = 35°μ = 0.1d = 19 mg = 9.81 m/s²
Wf = J
4.Medium
0.05 kgk = 200 N/mh = ?

A toy launcher has a vertical spring of stiffness 200 N/m. A 0.05 kg ball is placed on it and the spring is compressed by 5 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 = 0.05 kgk = 200 N/mx = 5 cmg = 9.81 m/s²
h = m
5.Hard
h = 3 mL = 4.5 mμ = 0.3k = 1000 N/m

A 5 kg block is released from rest at height 3 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 4.5 m long (μ = 0.3) and then runs onto a spring (k = 1000 N/m) on a smooth surface. Find the maximum compression x of the spring.

m = 5 kgh = 3 mL = 4.5 mμ = 0.3k = 1000 N/mg = 9.81 m/s²
x = cm
6.Hard
h = 3 mL = 5 mμ = 0.15k = 2000 N/m

A 1 kg block is released from rest at height 3 m on a smooth ramp. At the bottom it crosses a rough horizontal strip 5 m long (μ = 0.15) and then runs onto a spring (k = 2000 N/m) on a smooth surface. Find the maximum compression x of the spring.

m = 1 kgh = 3 mL = 5 mμ = 0.15k = 2000 N/mg = 9.81 m/s²
x = cm

Answer key

  1. 1. Ek = 686.7 J
  2. 2. v = 0.9729 m/s
  3. 3. Wf = 30.54 J
  4. 4. h = 0.5097 m
  5. 5. x = 40.23 cm
  6. 6. x = 14.86 cm

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