Advertisements
Advertisements
प्रश्न
A 100 kg gun fires a ball of 1 kg horizontally from a cliff of height 500 m. It falls on the ground at a distance of 400 m from the bottom of the cliff. Find the recoil velocity of the gun. (acceleration due to gravity = 10 ms–2)
Advertisements
उत्तर
Given, the mass of the gun (m1) = 100
Mass of the ball (m2) = 1 kg
Height of the cliff = 500 m
Horizontal distance travelled by the ball (x) = 400 m
From `h = 1/2 "gt"^2` .....(∵ Initial velocity in the downward direction is zero)
`500 = 1/2 xx 10 t^2`
`t = sqrt(100)` = 10 s
From `x = ut, u = x/t = 400/10` = 40 m/s
It v is the recoil velocity of gun, then according to the principle of conservation of linear momentum,
m1v = m2u
v = `(m_2u)/m_1 = 1/100 xx 40` = 0.4 m/s
APPEARS IN
संबंधित प्रश्न
From a rifle of mass 4 kg, a bullet of mass 50 g is fired with an initial velocity of 35 m s−1. Calculate the initial recoil velocity of the rifle.
Two objects, each of mass 1.5 kg are moving in the same straight line but in opposite directions. The velocity of each object is 2.5 m s−1 before the collision during which they stick together. What will be the velocity of the combined object after collision?
A shell of mass 0.020 kg is fired by a gun of mass 100 kg. If the muzzle speed of the shell is 80 m s–1, what is the recoil speed of the gun?
state whether momentum is scalar or vector.
Explain why, it is easier to stop a tennis ball than a cricket ball moving with the same speed.
Calculate the momentum of a toy car of mass 200 g moving with a speed of 5 m/s.
A man throws a ball weighing 500 g vertically upwards with a speed of 10 m/s.
- What will be its initial momentum ?
- What would be its momentum at the highest point of its flight ?
State the relation between the momentum of a body and the force acting on it.
A 10 g bullet travelling at 200 m/s strikes and remains embedded in a 2 kg target which is originally at rest but free to move. At what speed does the target move off ?
A body of mass 2 kg is at rest. What should be the magnitude of force which will make the body move with a speed of 30 m/s at the end of 1 s ?
The velocity of a body of mass 10 kg increases from 4 m/s to 8 m/s when a force acts on it for 2 s.
(a) What is the momentum before the force acts ?
(b) What is the momentum after the force acts ?
(c) What is the gain in momentum per second ?
(d) What is the value of the force ?
Name the law involved in the following situation :
the sum of products of masses and velocities of two moving bodies before and after their collision remains the same.
Explain why, a cricket player moves his hands backwards while catching a fast cricket ball.
Discuss the conservation of momentum in each of the following cases :
(i) a rocket taking off from ground.
(ii) flying of a jet aeroplane.
An unloaded truck weighing 2000 kg has a maximum acceleration of 0.5 m/s2. What is the maximum acceleration when it is carrying a load of 2000 kg ?
A man wearing a bullet-proof vest stands still on roller skates. The total mass is 80 kg. A bullet of mass 20 grams is fired at 400 m/s. It is stopped by the vest and falls to the ground. What is then the velocity of the man?
The rockets work on the principle of conservation of :
A girl riding a bicycle along a straight road with a speed of 5 ms–1 throws a stone of mass 0.5 kg which has a speed of 15 ms–1 with respect to the ground along her direction of motion. The mass of the girl and bicycle is 50 kg. Does the speed of the bicycle change after the stone is thrown? What is the change in speed, if so?
Two blocks P and Q of masses 0.3 kg and 0.4 kg, respectively, are stuck to each other by some weak glue as shown in the figure. They hang together at the end of a spring with a spring constant of k = 200 N/m. The block Q suddenly falls free due to the failure of glue, then the maximum kinetic energy of block P during subsequent motion will be ______ mJ.
