Question

A motorcycle and its driver has a mass of 145 kg. Answer the following questions about it, using correct units.

Answer 1

Answer:

(A) 45312.5 J

(B) 5075 J

(C) 62640 J

Explanation:

m = 145 kg

(a) v = 25 m/s

The energy possessed by the body by virtue of its motion is called kinetic energy. The formula for kinetic energy is given by

$K = \frac{1}{2}mv^{2}$

$K = \frac{1}{2}\times 145\times 25^{2}$

K = 45312.5 Joule

(b) h = 3.5 m

The energy possessed by the body by virtue of its position is called potential energy.

P = mgh

P = 145 x 10 x 3.5

P = 5075 Joule

(c) v = 28 m/s, h = 4 m

The sum of the kinetic energy and potential energy is called mechanical energy.

M.E. = 1/2 mv^2 + mgh

M.E. = 0.5 x 145 x 28 x 28 + 145 x 10 x 4

M.E. = 56840 + 5800

M.E. = 62640 Joule  

Answer 2

a) KE=0.5*mv^2==0.5*145*25^2=45312.5 J

b) PE=mgh=145*9.8*3.5=4973.5 J

c) ME=KE+PE=m(0.5v^2+gh)=62524 J