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# Tag Archives: t2

## Velocity and acceleration of a Ferrari !

A **Ferrari** covers120m from a standing start in 6sec at constant acceleration.Find its final velocity

(Shilvastar asked this)

**Answer**:

u=0 (Since it starts from rest)

t= 6s

s=120m

a=?

v=?

from

a=2 x 120/36=6.67 m/s^{2}

from v=u+at

v=40m/s

## Motion under gravity and time of fall

A body of mass m1 and another body of mass m2 are dropped from wqual heights.If time taken by the balls are t1 and t2 respectively then t1=t2. How ?

**Answer**:

The acceleration due to gravity is independent of mass of body. When two **different masses ** are dropped from the ** same height**, they will take **same time ** to reach the surface of earth.

## A body is dropped from a tower of height 96 m. Another body is thrown up from the ground after a second with a velocity of 40 m/s.When and where they will meet?

A body is dropped from a tower of height 96 m. Another body is thrown up from the ground after a second with a velocity of 40 m/s. When and where they will meet?

SOUNDARYA asked

Answer:

For the first body,

u=0 m/s

Let S=x (from top)

x=0.5 gt^{2 } ————— (1)

For the second body,

u=40 m/s

a=-g

S=96-x

96-x=40 t -0.5 gt^{2 } ———–(2)

(1) + (2) =>

96=40t

or

t=96/40 = 2.4 s

x= 0.5 g t^{2 }=**28.224 m** from top (taking g = 9.8 m/s^{2})

## Problem from relative velocity

A Boat covers certain distance between two spots in a river taking t1 hrs going downstream and t2 hrs going upstream. What time will be taken by boat to cover same distance in still water?

posted by STUTI

Answer: