Advertisements
Advertisements
प्रश्न
A stone of 1 kg is thrown with a velocity of 20 m s−1 across the frozen surface of a lake and comes to rest after travelling a distance of 50 m. What is the force of friction between the stone and the ice?
Advertisements
उत्तर
Mass of the stone (m) = 1kg
Distance travelled (s) = 50 m
Initial velocity of the stone (u) = 20 m/s
The final velocity of the stone (v) = 0 m/s
From the third equation of motion
v2 - u2 = 2as
02 - (20)2 = 2 × a × 50
02 - (20)2 = 100a
a = `(-400)/100`
a = -4 m s-2
The frictional force between the stone and ice
F = m × a
F = 1 × -4
= -4 N
Therefore, the frictional force between the stone and ice = -4 N
APPEARS IN
संबंधित प्रश्न
Using a horizontal force of 200 N, we intend to move a wooden cabinet across a floor at a constant velocity. What is the friction force that will be exerted on the cabinet?
What is the force which produces an acceleration of 1 m /s2 in a body of mass 1 kg ?
A girl weighing 25 kg stands on the tloor. She exerts a downward force of 250 N on the floor. What force does the floor exert on her ?
Do action and reaction act on the same body or different bodies ? How are they related in magnitude and direction ? Are they simultaneous or not ?
State Newton’s third law of motion and give two examples to illustrate the law.
According to the third law of motion, action and reaction :
Give a scientific reason.
Even though the magnitudes of action force and reaction forces are equal and their directions are opposite, their effects do not get cancelled.
Why do the action and reaction forces in a pair not cancel each other out?
In a hose pipe ejecting water, what is the reaction force?
What is the main characteristic of action and reaction forces?
