Advertisements
Advertisements
Question
An object of mass 100 kg is accelerated uniformly from a velocity of 5 ms−1 to 8 ms−1 in 6 s. Calculate the initial and final momentum of the object. Also, find the magnitude of the force exerted on the object.
Solution
Mass of the body = 100kg
The initial velocity of the body = 5m/s
The final velocity of the body = 8m/s
Time = 6s
The initial momentum of the body = Mass × Initial velocity of the object
= 100 × 5
= 500 kgm/s
Momentum of the body later = 100 × 8
= 800 kgm/s
Force (F) = `"Momentum change"/"Time"`
= `(800-500)/6`
= `300/6`
= `100/2`
Force = 50N
APPEARS IN
RELATED QUESTIONS
A 8000 kg engine pulls a train of 5 wagons, each of 2000 kg. along a horizontal track. If the engine exerts a force of 40000 N and the track offers a friction force of 5000 N, then calculate:
- the net accelerating force and
- the acceleration of the train.
An automobile vehicle has a mass of 1500 kg. What must be the force between the vehicle and road if the vehicle is to be stopped with a negative acceleration of 1.7 m s−2?
The following is the distance-time table of an object in motion:
| Time in seconds | Distance in metres |
| 0 | 0 |
| 1 | 1 |
| 2 | 8 |
| 3 | 27 |
| 4 | 64 |
| 5 | 125 |
| 6 | 216 |
| 7 | 343 |
- What conclusion can you draw about the acceleration? Is it constant, increasing, decreasing, or zero?
- What do you infer about the forces acting on the object?
Two persons manage to push a motorcar of mass 1200 kg at a uniform velocity along a level road. The same motorcar can be pushed by three persons to produce an acceleration of 0.2 m s−2. With what force does each person push the motorcar? (Assume that all persons push the motorcar with the same muscular effort.)
A large truck and a car, both moving with a velocity of magnitude v, have a head-on collision and both of them come to a halt after that. If the collision lasts for 1 s:-
(a) Which vehicle experiences the greater force of impact?
(b) Which vehicle experiences the greater change in momentum?
(c) Which vehicle experiences the greater acceleration?
(d)Why is the car likely to suffer more damage than the truck?
A car of mass 2400 kg moving with a velocity of 20 m s-1 is stopped in 10 seconds on applying brakes. Calculate the retardation and the retarding force.
A passenger in a moving train tosses a coin which falls behind him. This shows that the motion of train is :
Newton’s III law is applicable
State Newton’s laws of motion?
A force vector applied on a mass is represented as `vecF = 6hati - 8hatj + 10hatk` N and accelerates the mass at 1 ms-2. The mass of the body is ______.
