Question

A body of mass 60 Kg is pushed with just enough horizontal force to start it moving on a rough horizontal surface with coefficient static friction 0.5 and coefficient of kinetic friction 0.4 and the force continue to act afterwards , the time taken to acquire a velocity of 5 m/ s is ( g= 10 m/ s* 2) a) 5 s. b) 2.5 s. c) 10 s d) 4 s​

Answer 1

Explanation:

Correct option is

C

1m/s

2

The Uniting friction =μ

s

R

μ

s

mg=0.5×60×10=300N

Kinetic friction =μ

k

R=μ

k

mg

=0.4×60×10=240N

Force applied = 300 N

Net accelerating force

= Applied force - kinetic friction

⇒ ma = 300 - 240 = 60

⇒a=

60

60

=1m/s

2