Advertisements
Advertisements
Question
State Newton’s laws of motion?
Solution
- Newton’s First Law: Everybody continues to be in its state of rest or the state of uniform motion along a straight line unless it is acted upon by some external force.
- Newtons Second law: The force acting on a body is directly proportional to the rate of change of linear momentum of the body and the change in momentum takes place in the direction of the force.
- Newtons Third Law: For every action, there is an equal and opposite reaction. They always act on two different bodies.
APPEARS IN
RELATED QUESTIONS
A bullet of mass 10 g travelling horizontally with a velocity of 150 m s−1 strikes a stationary wooden block and comes to rest in 0.03 s. Calculate the distance of penetration of the bullet into the block. Also calculate the magnitude of the force exerted by the wooden block on the bullet.
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.
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.)
Explain the meaning of the following equation :
F = m x a
where symbols have their usual meanings
If a balloon filled with air and its mouth untied, is released with its mouth in the downward direction, it
moves upwards. Why ?
The acceleration produced by a force of 5 N acting on a mass of 20 kg in m/s2 is :
Deduce the equation of a force using Newton’s second law of motion.
Using the second law of motion, derive the relation between force and acceleration. A bullet of 10 g strikes a sand-bag at a speed of 103 m s-1 and gets embedded after travelling 5 cm. Calculate
(i) the resistive force exerted by the sand on the bullet
(ii) the time is taken by the bullet to come to rest.
Two blocks each of mass m lie on a smooth table. They are attached to two other masses as shown in the figure. The pulleys and strings are light. An object O is kept at rest on the table. The sides AB and CD of the two blocks are plane and made reflecting. The acceleration of two images formed in those two reflecting surfaces with respect to each other is ______.
