Question

A student pushes a 50 kg box of books on a flat surface with a force of 120 N at an angle of 60° on the horizontal. If the surface is friction free, how far does the box move in 5 seconds assuming it started moving from rest? a. 6.0 m

b. 8.5 m
c. 15 m
d. 4.6 m

Answer 1

c. 15 m

Step-by-step explanation:

We apply Newton's second law in the x direction:

∑Fₓ = m*a

120*cos(60°) = 50*a

`a = (120*cos(60^o))/(50)  = 1.2 (m)/(s^2)`

Block kinematics

The block moves with uniformly accelerated movement, so we apply the following formula to calculate the distance

`d = V_o*t + (1)/(2)*a*t^2`

`d = 0 + (1)/(2)*1.2*5^2`

d = 15m