Question

a block is moved from rest through a distance of 4m along a straight line path. the mass of the block is 5kg and the force acting on it is 20N. if kinetic energy acquired by the block be 40J. at what angle to the path the force is acting.

A) 30°
B) 60°
C) 45°
D) none

Answer 1

FS Cosθ = K.E
Cosθ = K.E / (F S)
Cosθ = 40 / (20 × 4)
Cosθ = 1 / 2
Cosθ = Cos60
θ = 60°

(B) is the correct option

Answer 2

Answer:

60°

Explanation:

work=change in k.e. ...work energy theorem

f.s cos thetha=k.e

20*4 cos thetha=40

cos thetha =40/80

cos thetha =1/2

thetha=60°