Question

A student pushes a 21-kg box initially at rest, horizontally along a frictionless surface for 10.0 m and then releases the box to continue sliding. If the student pushes with a constant 10 N force, what is the box's speed when it is released?

Answer 1

Answer:v=3.08 m/s

Explanation:

Given

mass of student $m=21 kg$

distance moved $d=10 m$

Force applied $F=10 N$

acceleration of system during application of force is a

$a=\frac{F}{m}=\frac{10}{21}=0.476 m/s^2$

using $v^2-u^2=2 as$

where v=final velocity

u=initial velocity

a=acceleration

s=displacement

$v^2-0=2\times 0.476\times 10$

$v=\sqrt{9.52}$

$v=3.08 m/s$