Advertisements
Advertisements
प्रश्न
A car is moving with a uniform velocity 30 ms-1. It is stopped in 2 s by applying a force of 1500 N through its brakes. Calculate the following values : The change in momentum of car.
Advertisements
उत्तर
Initial velocity, u = 30 m/s
Final velocity, v = 0
Time, t = 2s
Force, F = 1500 N
Here, a = (v - u)/t = (0 - 30)/ 2 = - 15 ms-2. Here, negative sign indicates retardation.
Now, F = ma.
Or, m = F/a = (1500/ 15) = 100 kg.
Change in momentum = Final momentum - Initial momentum
Or, Δp = m (v - u)
Or, Δp = 100 (0 - 30)
Or, Δp = 3000 kg m/s-1
APPEARS IN
संबंधित प्रश्न
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 person says that he measured the acceleration of a particle to be non-zero even though no force was acting on the particle.
Show that the rate of change of momentum = mass × acceleration. Under what condition does this relation hold?
Two balls A and B of masses m and 2 m are in motion with velocities 2v and v, respectively. Compare:
(i) Their inertia.
(ii) Their momentum.
(iii) The force needed to stop them in the same time.
The linear momentum of a body of mass m moving with velocity v is :
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 velocity acquired by the body.
Name the physical quantity which equals the rate of change of linear momentum.
Use Newton's second law to explain the following:
While catching a fast moving ball, we always pull our hands backwards.
A metre scale is moving with uniform velocity. This implies ______.
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?
