Question

un u
Valanced.
A1 kg mass falls from a height of 10 m into a sand box. What is the
cignt of 10 m into a sand box. What is the speed of the mass just before hitting the sand
box? If it travels a distance of 2 cm into the sand before coming to rest,
[1]
cance of 2 cm into the sand before coming to rest, what is the average retarding force
(a) 12 ms' and 3600 N
(b) 14 ms and 4900 N
(c) 16 ms' and 6400 N
(d) 18 ms and 8100 N​

Answer 1

The speed of the mass just before hitting the sand  box is 14 m/s and the average retarding force is 4900 N.

Explanation:

Potential energy of ball will converted to K.E

SO, mgh =   mv^2 / 2  ⇒ v=  √2gh

​V =  √2 × 9.8 × 10  = 14 m/s

When object will pass through sand it will loose its K.E to overcome the resisting force by sand.

Now Fs = mv^2 / 2 = 98

F = 98 / 0.02 = 4900 N

Thus the speed of the mass just before hitting the sand  box is 14 m/s and the average retarding force is 4900 N.