J J Science Academy

Subject: Physics

Topic: 4. Linear kinematics

SubTopic: 4.5 Distance travelled in nth second

Test Type: NEET

1) An uniformly accelerated body travels a distance of 24 m in $5^{th}$ second of its motion and 44 m in $15^{th}$ sec of its motion. The acceleration of the particle will be

1) $1 m / s^{2}$

2) $2 m / s^{2}$

3) $4 m / s^{2}$

4) $0.5 m / s^{2}$

Hint: $s_{n}=u+\frac{1}{2} g(2n-1)$ $24=u+\frac{9a}{2}$ (i) $44=u+\frac{29a}{2}$ (ii) (ii) - (i) gives $20=10a$ $a=2 m / s^{2}$

2) A body, starting with some velocity, experiences uniform acceleration. It travels a distance of 20 m in $5^{th}$ second and 36 m in $9^{th}$ second. The acceleration of the particle (in $m / s^{2}$ ) is

1) 4

2) 2

3) 6

4) 8

Hint: $s_{n}=u+\frac{1}{2} g(2n-1)$ $20=u+\frac{9a}{2}$ (i) 36 = u + 17a (ii) - (i) gives 16=4a a = 4 m/s2

3) A particle starts moving along a straight line with velocity ' $u$ ' and a constant acceleration ' $a$ ', the initial velocity is

1) $1 m / s$

2) $-1 m / s$

3) $2 m / s$

4) $-2 m / s$

Hint: $s_{9}=u+\frac{1}{2}(4)[2(9)-1]$ $36=u+34$ $u=2 m / s$

4) A particle starts moving along a straight line with velocity ' $u$ ' and a constant acceleration ' $a$ ', the distance it travels in $15^{th}$ second is

1) 54 m

2) 58 m

3) 60 m

4) 64 m

Hint: $s_{n}=u+\frac{1}{2} g(2n-1)=2+\left[\frac{1}{2} \times 4 \times 29\right]=2+58=60m$