Question

A constant retarding force of 50N is applied to a body of mass 20kg moving initially with a speed of 15ms-1.How long does the body take to stop?​

Answer 1

Answer:

Explanation:

v=u+at, where,

v is final velocity,

u is the initial velocity,

a is acceleration, and,

t is the time.

It is given that the force, F=−50 N (retarding) and the mass m=20 kg.

⇒a=−5020=−2.5 m/s2.

It is also given that u=15 m/s and that we want to determine the time when v=0.

⇒0=15−2.5t.

⇒t=152.5=6 s.

⇒ The time taken by the body to stop is 6 s.

Answer 2

Explanation:

From Newton's IInd law of motion F nne =ma

From given data in question F=−50N;m=20kg;u=15m/s;v=0m/s

⇒a= −50/20

=−2.5m/s ^2

Using kinematics equation v=u+at

where v and u are final and initial velocities and a is acceleration and t is time in s;

v=0;u=15m/s;a=−2.5m/s ^2

⇒t= 15/2.5

=6s

I hope this is help you..