Question

A car of mass 1500 kg is moving with a velocity of 30 m/s. If the velocity-time graph for this car is a horizontal line parallel to the time axis, then the velocity of the car at the end of 25 s will be

Answer 1

The body is displaced from

r

1

to

r

2

.

Therefore, displaeement of the body is,

s

=

r

2

−

r

1

=(

i

^

+

j

^

+

k

^

)−(2

i

^

+3

j

^

+

k

^

)=(−

i

^

−2

j

^

)m

Now, work done by the force is:

W=

F

⋅

s

=(2

i

^

+3

j

^

+4

k

^

)⋅(−

i

^

−2

j

^

)

=(2)(−1)+(3)(−2)

=−8J