If the block P shown in the figure given below is to be kept at rest, what will be the magnitude of force F? (Forces on block: 10 N leftward and 2 N rightward at top; 15 N leftward and 15 N rightward at bottom; F is rightward)

For the block P to be at rest, the net force on it must be zero. Summing horizontal forces: rightward forces are 2 N + 15 N + F, and leftward forces are 10 N + 15 N. Setting them equal: 2 + 15 + F = 10 + 15, which gives 17 + F = 25, so F = 8 N. Therefore, a force of 8 N is required to keep block P at rest.