Uniform circular motion 9th (lec 10)

 video lectures forUniform circular motion 

Question 1: The ratio of maximum heights reached by two bodies projected vertically up is `a : b`, then the ratio of their initial velocities of is 

 (a) `a : b` 

(b) `a^{2} : \sqrt{b}`  

(c) `\sqrt{a} : \sqrt{b}`  

(d) `\sqrt{b} : \sqrt{a}`

Question 2: A body is projected horizontally with a velocity `23 ms^{-1}`  from a height of `5 m`. What is the velocity of the body on reaching the ground?

a) `5\sqrt{3} ms^{-1}`

b) `10\sqrt{3} ms^{-1}`

c) `10\frac{\sqrt{3}}{3} ms^{-1}`

d) none of above

Question 3: What remains constant in uniform circular motion?

a) Velocity

b) Speed

c) Displacement

d) Direction

Question 4: A particle revolves along a circle with a uniform

speed. The motion of the particle is ______.

a) one-dimensional 

b) two-dimensional

c)  translatory  

d) oscillatory

Question 5:  A particle revolves along a circle with a uniform speed. The motion of the particle is ______.

 

(a) one dimensional  

(b) two dimensional  

(c) translatory  

(d) oscillatory

Question 6: A car accelerates from `18 kmh^{-1}` to `36 kmh^{-1}` with uniform acceleration in `5 s`. Find the distance covered by this time.

a) `30 m`

b) `25 m`

c) `12.5 m`

d) `37.5 m`

Question 7: If a body starts from rest and moves with uniform acceleration, then  

 

(a) `v ∝ t`  

(b) `s ∝ t`  

(c) `v ∝ s`  

(d) `s ∝\sqrt{t}`

Question 8: The ratio of the times taken by a body moving with uniform acceleration in reaching two points `P` and `Q` along a straight line path is `1: 2`. If the body starts from rest, then the ratio of the distances of `P` and `Q` from the starting point is  

(a) `4 : 1`  

(b) `1 : 4`  

(c) `2 : 3`  

(d) `3 : 1`

Question 9: A body starts from rest and moves with uniform acceleration for `2 s`. It then decelerates uniformly for `3 s` and stops. If deceleration is, `4 ms^{-2}` the acceleration of the body is 

(a) `10 ms^{-2}`  

(b) `8.7 ms^{-2}`  

(c) `4 ms^{-2}`  

(d) `6 ms^{-1}`

Question 10: A particle revolves along a circle with a uniform speed. The motion of the particle is

   

(a) one dimensional  

(b) two-dimensional  

(c) translatory  

(d) oscillatory

Question 11: A bus starts from rest and travels with a uniform acceleration of `0.1 ms^{-2}` for `2 min`. Calculate

1. Speed achieved

2. Distance covered

a) `12 ms^{-1}` , `720 m`

b) `10 ms^{-1}`, `720 m`

c) `12 ms^{-1}`, `620 m`

d) `12 ms`, `720 m`

Question 12: A train is moving with a speed of `90 kmh^{-1}`. When the brakes are applied, it produces a uniform acceleration of `-0.5 ms^{-2}`. What is the distance covered by the train before coming to rest?

a) `450 m`

b) `600m`

c) `625 m`

d) `520 m`

Answer key

Q1 (c), Q2 (a), Q3 (b), Q4 (b), Q5 (b), Q6 (d), Q7 (a), Q8 (b), Q9 (d), Q10 (b), Q11 (a), Q12 (c)