Advertisements
Advertisements
प्रश्न
How long will a stone take to fall to the ground from the top of a building 80 m high
Advertisements
उत्तर
Height, s = 80m
g = 10 m/s2
Using the second equation of motion,
S = ut + (1/2) gt2
Or, 80 = 0+ (1/2) (10) (t) 2
Or, (t) 2 = 16
Or, t = 4s
APPEARS IN
संबंधित प्रश्न
A batsman deflects a ball by an angle of 45° without changing its initial speed which is equal to 54 km/h. What is the impulse imparted to the ball? (Mass of the ball is 0.15 kg.)
A man has fallen into a ditch of width d and two of his friends are slowly pulling him out using a light rope and two fixed pulleys as shown in the following figure. Show that the force (assumed equal for both the friends) exerted by each friend on the road increases as the man moves up. Find the force when the man is at a depth h.
Consider the Atwood machine of the previous problem. The larger mass is stopped for a moment, 2.0 s after the system is set into motion. Find the time that elapses before the string is tight again.
Consider the situation shown in the following figure All the surfaces are frictionless and the string and the pulley are light. Find the magnitude of acceleration of the two blocks.
A body of mass m moving with a velocity v is acted upon by a force. Write an expression for change in momentum in each of the following cases: (i) When v << c, (ii) When v → c and (iii) When v << c but m does not remain constant. Here, c is the speed of light.
Two balls A and B of masses m and 2 m are in motion with velocities 2v and v, respectively. Compare:
(i) Their inertia.
(ii) Their momentum.
(iii) The force needed to stop them in the same time.
How can Newton's first law of motion be obtained from the second law of motion?
A ball is thrown vertically upwards. It returns 6 s later. Calculate the greatest height reached by the ball. (Take g = 10 m s−2)
Multiple Choice Question. Select the correct option.
The impulse of a body is equal to:
Multiple Choice Question. Select the correct option.
Which of the following are vector quantities?
