Question

A long stick rests on the surface. A
person standing 10 m away from the
stick. With what minimum speed an
object of mass 0.5 kg should he thrown
so that it hits the stick. (Assume the
coefficient of kinetic friction is 0.7).​

Answer 1

Yeshwanth2144 follow this in instagram

Answer 2

Given:

Distance of the stick from the person = 10 m

Mass of the object = 0.5 kg

Coefficient of kinetic friction μ = 0.7

To find:

Minimum speed with which the object must be thrown to hit the stick.

Solution:

If the object needs to hit the stick then it has to travel 10 m.

Work done in moving the object = Force * displacement

Where Force = μ*mg

Therefore work = μmg*10 = 0.7*0.5*10*9.8 = 34.3 J

This work done will be spent in the kinetic energy of the body:

Kinetic energy = 1/2*mv²

Therefore 1/2*mv² = 34.3

v² = (34.3*2) / 0.5

v² = 137.2

v = 11.71 m/s

Therefore the minimum velocity must be 11.71 m/s.