Advertisements
Advertisements
Question
If you jump barefoot on a hard surface, your legs are injured. But they are not injured if you jump on a soft surface like sand or pillow. Why?
Advertisements
Solution
In both the cases, change in momentum is same but the time interval during which momentum changes to zero is less in the first case. So, by `"F"="dp"/"dt"`, force in the first case will be more. That's why we are injured when we jump barefoot on a hard surface.
APPEARS IN
RELATED QUESTIONS
Name the scientist who gave the laws of motion.
Fill in the following blank with suitable word :
Newton’s first law of motion is also called Galileo’s law of ………………………
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’.
Find the acceleration produced by a force of 5 N acting on a mass of 10 kg.
Name the law involved in the following situation :
if there were no friction and no air resistance, then a moving bicycle would go on moving for ever.
The acceleration of a particle is zero, as measured from an inertial frame of reference. Can we conclude that no force acts on the particle?
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?
A block of 2 kg is suspended from a ceiling by a massless spring of spring constant k = 100 N/m. What is the elongation of the spring? If another 1 kg is added to the block, what would be the further elongation?
An object of mass 2 kg is sliding with a constant velocity of 4 m/s on a frictionless horizontal table. The force required to keep this object moving with the same velocity is :
State Newton's first law of motion.
Explain the following :
After alighting from a moving bus , one has to run for some distance in the direction of bus in order to avoid falling .
A force of 600 dynes acts on a glass ball of mass 200 g for 12 s. If initially, the ball is at rest, find
- Final velocity
- Distance covered.
What do you mean by inertia of motion?
The greater is the __________ the greater is the inertia of an object.
Differentiate between gravitational mass and inertial mass.
When a bus suddenly takes a tum, the passengers are thrown outwards because of
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).
What does inertia measure in an object?
