Advertisements
Advertisements
Question
State Newton’s first law of motion. Give two examples to illustrate Newton’s first law of motion.
Advertisements
Solution
According to Newton’s first law of motion:
A body at rest will remain at rest and a body in motion will continue in motion in a straight line with a constant velocity, unless it is compelled by an external force to change its state of rest or of uniform motion.
Examples:
(a) A book lying on a table cannot change its state of rest unless an external force is applied on the book.
(b) A car set free on a sloppy road will continue to be in motion unless an external force applied by hands or brakes to bring the car to rest.
APPEARS IN
RELATED QUESTIONS
Name the scientist who gave the laws of motion.
A moving bicycle comes to rest after sometime if we stop pedalling it. But Newton’s first law of motion says that a moving body should continue to move for ever, unless some external force acts on it. How do you explain the bicycle case ?
Name the physical quantity whose unit is ‘newton’.
It is sometimes heard that the inertial frame of reference is only an ideal concept and no such inertial frame actually exists. Comment.
A plumb bob is hung from the ceiling of a train compartment. If the train moves with an acceleration 'a' along a straight horizontal track , the string supporting the bob makes an angle tan−1 (a/g) with the normal to the ceiling. Suppose the train moves on an inclined straight track with uniform velocity. If the angle of incline is tan−1 (a/g), the string again makes the same angle with the normal to the ceiling. Can a person sitting inside the compartment tell by looking at the plumb line whether the train is accelerating on a horizontal straight track or moving on an incline? If yes, how? If not, then suggest a method to do so.
A particle is observed from two frames S1 and S2. Frame S2 moves with respect to S1with an acceleration a. Let F1 and F2 be the pseudo forces on the particle when seen from S1 and S2, respectively. Which of the following is not possible?
Give qualitative definition of force on the basic of Newton's first law of motion.
In a legend, the hero-kid kicked a toy pig so that it is projected with a speed greater than that of its cry. If the weight of the toy pig is assumed to be 5 kg and the time of contact 0.01 sec., the force with which the hero-kid kicked him was ______.
(Speed of cry = 330 m/s)
A balloon has mass of 10 g in air. The air escapes from the balloon at a uniform rate with velocity 4.5 cm/s. If the balloon shrinks in 5 s completely. Then, the average force acting on that balloon will be (in dyne).
How is force defined according to Newton’s First Law?
