Work and Energy (Advanced)

CBSE Science. Optional Advanced level: conservative and non-conservative forces, W = −ΔU, Hooke's law, energy of a spring, friction and energy. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.

Open a printable sample sheet Cheat sheet: formulas and key points

Sample questions

Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.

Section A · multiple choice

1.
A spring with spring constant 120 N/m is pulled by a force of 14.4 N. The extension is:
1. 120 cm
2. 0.14 cm
3. 14 cm
4. 12 cm
Answer
(d) 12 cm
x = F ÷ k = 14.4 ÷ 120 = 0.12 m
2.
A spring of spring constant 950 N/m is stretched by 19 cm. The elastic potential energy stored is:
1. 17.15 J
2. 34.30 J
3. 90.25 J
4. 171,475 J
Answer
(a) 17.15 J
U = ½kx² = ½ × 950 × (0.19)²
3.
How much work is done in stretching a spring (k = 400 N/m) from an extension of 1 cm to 7 cm?
1. 0.98 J
2. 0.72 J
3. 1.92 J
4. 0.96 J
Answer
(d) 0.96 J
W = ½k(x₂² − x₁²) = ½ × 400 × (0.07² − 0.01²)

Section B · short answer

4.
A force of 23.2 N stretches a spring by 29 cm. Find the spring constant.
Answer
80 N/m
k = F ÷ x = 23.2 ÷ 0.29
5.
Find the elastic potential energy stored in a spring of spring constant 480 N/m when it is compressed by 13 cm. (Give the answer to 2 decimal places where needed.)
Answer
4.06 J
½kx² = ½ × 480 × 0.13²

Section C · long answer

6.
A spring gives these readings: 2 cm for 4 N, 4 cm for 8 N, 6 cm for 12 N, 8 cm for 16 N. (a) Find the spring constant. (b) Find the work done in stretching it from 2 cm to 4 cm. (c) Find the energy stored at 8 cm. (d) A 2 kg block attached to it is released from 8 cm on a smooth floor. Find its greatest speed. (Give the answer to 2 decimal places where needed.)
Answer
(a) 200 N/m; (b) 0.12 J; (c) 0.64 J; (d) 0.8 m/s
(a) k = F ÷ x; (b) area under the graph = ½k(x₂² − x₁²); (c) ½k(0.08)²; (d) ½kx² = ½mv²

Fresh sheets for your child

In the app, every Work and Energy (Advanced) sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.

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