Question

Numericals Problems
[Assume g=10m/s?]
If a girl is running along a straight road with a uniform velocity 1,5 mls, find her
acceleration
A car travelling at a velocity of 15 ms due north speeds up uniformly to a velocity of
30 ms' in 3 seconds. Calculate its acceleration,
(Ang: 5m/s)
A bus is travelling at a speed of 60 km/hour. On seeing a boy 11 m ahead on the road,
the driver of the bus applies brakes and the bus stops at a distance of 10 m. What is its
retardation and how long does it take to come at rest? (Ans: 13.89 ms/2, 1.26)
A jeep starts from the state of rest. If its velocity becomes 60 km/hr in 5 minutes, ()
What is the acceleration of the jeep? (ii) What is the distance covered by the jeep?
(Ans: 0.056 m/s, 2500 m)
A car is moving with a velocity of 45 km/h. The driver presses the brakes and the
car comes to rest in 3 seconds. What is its retardation? How far does it move before
coming to rest?
(Ans: 4.17 m/s, 18.74 m)just ​

Answer 1

Answer:

Explanation:

Initial speed of the car is u.

Final speed of the car v=0

Let the retardation of the  car be a.

Using  v  

2

−u  

2

=2aS

Or  0−u  

2

=2aS

⟹ S∝u  

2

   (for same a)

Given :  S=40m    u  

′

=2u

∴  

S

S  

′

 

​  

=  

u  

2

 

(u  

′

)  

2

 

​  

=2  

2

 

Or    

40

S  

′

 

​  

=4

⟹  S  

′

=160m