20. When a stone is falling from a mountain, its initial velocity is z

1.	20. When a stone is falling from a mountain, its initial velocity is zero and theacceleration due to gravity is 9.8 m/s2. Velocity of the stone is given by9.8t. Draw its graph and find out the velocity of the stone 4 seconds afterICBSE SP 2011]the start.
Answer» Velocity of the stone at timet, v= 9.8t Whent= 4 sec, v= 9.8 × 4 m/sec = 39.2 m/sec Thus, velocity of the stone after 4 second is 39.2 m/sec.

20. When a stone is falling from a mountain, its initial velocity is zero and theacceleration due to gravity is 9.8 m/s2. Velocity of the stone is given by9.8t. Draw its graph and find out the velocity of the stone 4 seconds afterICBSE SP 2011]the start.

Answer»

Velocity of the stone at timet,

v= 9.8t

Whent= 4 sec,

v= 9.8 × 4 m/sec = 39.2 m/sec

Thus, velocity of the stone after 4 second is 39.2 m/sec.