Question

Starting from rest and height of 7 m, a 3kg object slides down a 30degrees incline, reaching the bottom with a speed of 10m/s . what is the work done by friction? please elaborate.

Answer 1

The work done by the friction is 55.8 J.

Step-by-step explanation:

Given that,

Height h = 7 m

Mass of the object = 3 kg

Angle = 30°

Speed = 10 m/s

The initial potential energy of the object is converted in to the kinetic energy at the bottom of the incline and the work done by the friction

`mgh=(1)/(2)mv^2+W`

Where, m = mass of the object

v = final velocity

g = acceleration due to gravity

h = height

Put the value in the equation

`3*9.8*7=(1)/(2)*3*(10)^2+W`

`W = (205.8-150)\ J`

`W=55.8\ J`

Hence, The work done by the friction is 55.8 J.