Question

calculate the work done to move a car 2000kg on rest to 72 per hour​

Answer 1

Answer:

Breaking force is 20 kNand time is 2sec.

Step-by-step explanation:

Given,

Mass of car, M=2000kg

Velocity, V=72×

18

5

=20ms

−1

Apply kinematic equation of motion

v

2

−u

2

=2as

0−20

2

=2a×20

a=−10ms

−2

Breaking force, F=ma=2000×10=20 kN

Apply first kinematic equation

v=u+at

t=

a

v−u

=

−10

0−20

=2 sec

Breaking force is 20 kNand time is 2sec

Answer 2

Answer:

Given,

Mass of car, M=2000kg

Velocity, V=72×

18

5

=20ms

−1

Apply kinematic equation of motion

v

2

−u

2

=2as

0−20

2

=2a×20

a=−10ms

−2

Breaking force, F=ma=2000×10=20 kN

Apply first kinematic equation

v=u+at

t=

a

v−u

=

−10

0−20

=2 sec

Breaking force is 20 kNand time is 2