Question

If it is given that object is moving with velocity 20m/s than it is initial velocity or final velocity

Answer 1

Answer:

Applied force  

F

(

t

)

=

(

−

22.0

m

−

233.7

m

t

)

N

Explanation:

Initial velocity  

u

=

20

m

s

−

1

. Final velocity  

v

=

0

, distance traveled  

=

4

m

.

The applicable kinematic equation for a constant acceleration is

v

2

−

u

2

=

2

a

s

⇒

0

2

−

20

2

=

2

a

×

4

⇒

a

=

−

400

8

=

−

50

m

s

−

2

Let us find out for what time this retarding force is applied.

Using the other kinematic equation

v

=

u

+

a

t

we get

0

=

20

+

(

−

50

)

t

t

=

20

50

=

0.4

s

We see that the object takes more time than given in the question to come to stop. This implies that it is not a case of constant deceleration.

Explanation: