Question
The graph shows how the length of a spring varies with the force applied to it.
The spring has unstretched length $L_{0}$. When a force F is applied, the spring has length L1.
What is the work done in stretching the spring to length $L_{1}$?
(A) $\frac{1}{2}FL_{1}$
(B) $\frac{1}{2}F$($L_{1}-L_{0}$)
(C) $FL_{1}$
(D) F$L_{1}-L_{0}$
Answer/Explanation
Ans: B
Question
A child holds a thin metal wire that is attached to a kite. The graph shows how the extension of the wire varies with its tension.
A gust of wind increases the tension from 100 N to 150N.
What is the change in the elastic potential energy of the wire caused by the gust of wind?
(A) 3.8mJ
(B) 19mJ
(C) 34mJ
(D) 38mJ
▶️Answer/Explanation
Ans: B
Question
A variable force is applied to ensure that a constant power is supplied to a train.
Which graph best shows the variation of the force F applied with the velocity v of the train?
▶️Answer/Explanation
Ans: A
Question
The force–extension graph for a spring is shown.
What represents the work done to extend the spring?
(A) the area under the graph
(B) the gradient of the graph
(C) the reciprocal of the gradient of the graph
(D) twice the area under the graph
▶️Answer/Explanation
Ans: B