Question

If a block moving up an inclined plane at 30° with a velocity of 5 ms 1, stops after 0.5s, then coefficient
kinetic friction will be nearly
(1) 0.5
(2) 0.9
(3) 0.2
(4) 0.6​

Answer 1

Explanation:

First find acceleration

$a = \frac{0 - 5}{0.5} = 10$

As you can see in diagram

ma = mgsin30°+ f

ma = mg sin30° + u mg cos 30°

$a = g \times \frac{1}{2} + \mu \times g \times \frac{ \sqrt{3} }{2} \\ 10 = 10 \times \frac{1}{2} + \mu \times 10 \times \frac{ \sqrt{3} }{2} \\ \mu = \frac{1}{ \sqrt{3} }$