Question

The time taken by a body projected upward with
velocity 9.8m/s from top of tower of height 39.2m to
reach the ground is
1) 2sec 2) 4 sec 3) 6 sec 4) 8 sec
20. A 1 kg hammer moving with velocity 5m/s strikes a
nail for 0.002second average force exerted on the
nail is -----
1) 2500N 2) 3000N
3) 2000N 4) 2900N
21. A body is dropped from height of 10m the
momentum of body when it reach the ground
(m=5kg)
1) 70kgm 2) 70 kg m/s
3) 70 gm cm 5) 70kg m/s2

22. A force produces an acceleration 16m/s2

in a mass

0.5kg and an acceleration 4m/s2

in an unknown mass
when applied separately. If both the masses are tied
together what is the acceleration under same force
1) 3.2m/s2

2) 2.2m/s2

3) 4.2m/s2

4) 5.2m/s2

23. A ball hit the wall vertically with velocity U m/s and
rebounds with same velocity then impulse on ball by
wall is ----(mass of ball is m )
1) 2mu towards the wall
2) 2mu away from wall
3) mu along the wall
4) 2mu along the wall
24. A shell of mass 5kg is exploded in to 2:3 ratio and
bigger mass moving with velocity 6m/s then the
velocity of smaller mass is ----
1) 6m/s 2) 3m/s 3) 2m/s 4) 9m/s
25. A ball of mass 0.01kg travelling at 2m/s hit a wall
and rebounds without change its speed. If the ball
remains in contact with the wall for 0.01s.Then the
force exerted by the ball on the wall is
1) 0.05N 2) 40N 3) 4N 4) 0.04N

Answer 1

Answer:

I am getting confused dear ask it shortly

Explanation:

hope it will help you dear

Answer 2

Answer:

Explanation:

19) 4 sec

v = 9.8m/s, u=0, h=39.2m, t=?

v = h/t

9.8 = 39.2/ t

t = 39.2/9.8

t = 4sec

20) 2500N

m= 1kg, v= 5m/s, t= 0.002sec

F= ma , where F = force, m= mass, a= acceleration

a= (v - u)/t

= (5 - 0)/0.002

= 2500m/s^2

F= 1 x 2500

= 2500N

21) Momentum = mass x velocity

v = sq. root (2gh)

v = sq. root (2 x 10 x 10)

v = sq. root 200

P = mv

P = 5 x sq. root 200

P = 70kgm/s