Question

a car acquires a velocity of 72 km/hr in 10 seconds starting from rest.Find acceleration,the average velocity,the distance travelled in this time

Answer 1

Hey there !

Initial Velocity = u = 0

Final velocity = v = 72 km/hr = 72 x 5/18 = 20 m/s

Time = t = 10 sec

Acceleration = a

Equation of motion :-

v = u + at
20 = 0 + 10a

a = 20/10

a = 2 m/s²

displacement = distance traveled = s

Equation of motion :-
v² - u² = 2as

20² = 2 × 2 × s

400 = 4s

s = 400/4

s = 100 m

Average velocity = displacement / time

= 100 / 10
= 10 m/s

Hope this helps you !

Answer 2

Hi friend,

Initial velocity,u=0

Final velocity, v=72 km/hr=72×5/18=20 m/s

[1 km/hr=5/18 m/s]

Time,t=10 s

We know that,

v=u+at

20=0+a(10)

20=10a

a=20/10=2 m/s²

distance travelled=displacement=s

v²-u²=2as

(20)²-(0)²=2(2)(s)

400=4s

s=400/4=100 m

Average velocity =displacement/time

Average velocity=100/10

=10 m/s

hope it helps