# A wooden block of mass 10 g is dropped from the top of a tower 100 m high. Simultaneously, a bullet of mass 10 g is fired from the foot of the tower vertically upwards with a velocity of 100 m/s. If the bullet is embedded in it, how high will the block rise above the top of tower before it starts falling? ) a) 75 m b) 85 m c) 80 m d) 10 m

## Question ID - 100305 :- A wooden block of mass 10 g is dropped from the top of a tower 100 m high. Simultaneously, a bullet of mass 10 g is fired from the foot of the tower vertically upwards with a velocity of 100 m/s. If the bullet is embedded in it, how high will the block rise above the top of tower before it starts falling? ) a) 75 m b) 85 m c) 80 m d) 10 m

3537

Answer Key : (a) -

(a)

The bullet and block will meet after time

During this time, distance travelled by the block,

Distance travelled by the bullet,

m

Velocity of the bullet before collision,

m/s

Velocity of the block before collision,

m/s

Let be the combined velocity after collision

According to the law of conservation of momentum,

or

(Velocity in upward direction is considered positive)

Solving, we get  m/s

Maximum height risen by the block m

Height reached above the top of the tower is

m

Next Question :
 Sympathetic nerve accelerates heart beat due to 1) Adrenaline 2) Nor-adrenaline 3) Insulin 4) Glucagon