Advertisements
Advertisements
प्रश्न
A woman throws an object of mass 500 g with a speed of 25 ms1.
- What is the impulse imparted to the object?
- If the object hits a wall and rebounds with half the original speed, what is the change in momentum of the object?
Advertisements
उत्तर
Mass of the object (m) = 500 g = 0.5 kg
Speed of the object (v) = 25 m/s
a. Impulse imparted to the object = Change in momentum
= mv – mu
= m(v – u)
= 0.5(25 – 0)
= 12.5 N-s
b. Velocity of the object after rebounds
= `- 25/2` m/s
v' = – 12.5 m/s
∴ Change in momentum = m(v’ – v)
= 0.5 (– 12.5 – 25)
= – 18.75 N-s
APPEARS IN
संबंधित प्रश्न
A rocket with a lift-off mass 20,000 kg is blasted upwards with an initial acceleration of 5.0 m s–2. Calculate the initial thrust (force) of the blast.
A stone of mass m tied to the end of a string revolves in a vertical circle of radius R. The net forces at the lowest and highest points of the circle directed vertically downwards are: [Choose the correct alternative]
| Lowest Point | Highest Point | |
| a) | mg – T1 | mg + T2 |
| b) | mg + T1 | mg – T2 |
| c) | `mg + T1 –(m_v_1^2)/R` | mg – T2 + (`mv_1^2`)/R |
| d) | `mg – T1 – (mv)/R` | mg + T2 + (mv_1^2)/R |
T1 and v1 denote the tension and speed at the lowest point. T2 and v2 denote corresponding values at the highest point.
A free 238U nucleus kept in a train emits an alpha particle. When the train is stationary, a nucleus decays and a passenger measures that the separation between the alpha particle and the recoiling nucleus becomes x at time t after the decay. If the decay takes place while the train is moving at a uniform velocity v, the distance between the alpha particle and the recoiling nucleus at a time t after the decay, as measured by the passenger, is
Find the acceleration of the blocks A and B in the three situations shown in the following figure.
In the following figure shows a man of mass 60 kg standing on a light weighing machine kept in a box of mass 30 kg. The box is hanging from a pulley fixed to the ceiling by a light rope, the other end of which is held by the man himself. If the man manages to keep the box at rest, what is the weight recorded on the machine? What force should he exert on the rope to record his correct weight on the machine?
A block is kept on the floor of an elevator at rest. The elevator starts descending with an acceleration of 12 m/s2. Find the displacement of the block during the first 0.2 s after the start. Take g = 10 m/s2.
State the Newton's second law of motion. What information do you get from it?
Write the mathematical form of Newton's second law of motion. State the conditions if any.
A force of 10 N acts on a body of mass 2 kg for 3 s, initially at rest. Calculate : The velocity acquired by the body
A force acts for 10 s on a stationary body of mass 100 kg, after which the force ceases to act. The body moves through a distance of 100 m in the next 5 s. Calculate : The magnitude of the force
Calculate the velocity of a body of mass 0.5 kg, when it has a linear momentum of 5 Ns.
Define Newton’s second law of motion.
State Newton's second law of motion.
A body of mass 400 g is resting on a frictionless table. Find the acceleration of the body when acted upon by a force of 0.02 N.
What do you mean by the conservation of momentum? Briefly, explain the collision between two bodies and the conservation of momentum.
The INCORRECT statement about Newton's second law of motion is
The position time graph of a body of mass 2 kg is as given in figure. What is the impulse on the body at t = 0 s and t = 4 s.
Why does a child feel more pain when she falls down on a hard cement floor, than when she falls on the soft muddy ground in the garden?
Why is catching a slow-moving ball easier than catching a fast-moving ball?
How does moving your hand backward while catching a cricket ball reduce pain?
