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
If action is always equal to the reaction, explain how a horse can pull a cart.
Explain, why is it difficult for a fireman to hold a hose, which ejects large amounts of water at a high velocity.
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 ?
Why does a gunman get a jerk on firing a bullet ?
If a man jumps out from a boat, the boat moves backwards. Why ?
Explain why, a runner presses the ground with his feet before he starts his run.
According to the third law of motion, action and reaction :
Complete a sentence and explain it.
The working of a rocket depends on Newton's ______ law of motion.
Consider a frame that is made up of two thin massless rods AB and AC as shown in the figure. A vertical force `vec"P"` of magnitude 100 N is applied at point A of the frame.
Suppose the force is `vec"P"` resolved parallel to the arms AB and AC of the frame.
The magnitude of the resolved component along the arm AC is xN.
The value of x, to the nearest integer, is ______.
[Given: sin(35°) = 0.573, cos(35°) = 0.819, sin(110°) = 0.939, cos(110°) = –0.342]
