A car is moving with uniform acceleration. It covers 200 m in 2 sec and 220 m

⇦

⇨

A car is moving with uniform acceleration. It covers 200 m in 2 sec and 220 m in next 4 sec. The velocity of car at the end of 7th second from start is

Options

(a) 1 m/s
(b) 0.1 m/s
(c) 10 m/s
(d) 20 m/s

Correct Answer:

10 m/s

Explanation:

For first 2 second
S = 2u +1/2α (2)²
200 = 2u + 2α
or u + α = 100 …(i)
For first 2 + 4 = 6 second
S = 200 + 220 = 420 m
420 = 6u + 36/2 α
420 = 6u + 18α ⇒ 420 = 6(u + 3α)
u + 3α = 420/6 = 70 …(ii)
Solving equation (i) and (ii)
α = -15 m/sec²
This is the retardation.
Using these formula V=ut+1/2 αt²
200 = u+1/2 (-15)(2)²
u = 115
Hence velocity after 7 second is
V = u+αt
= 115 + (–15) x 7
= 10 m/sec.

Related Questions:

1. A cricketer can throw a ball to a maximum horizontal distance of 100 m. With the same
2. The particle executing simple harmonic motion has a kinetic energy K₀cos²ωt.
3. A cyclist is riding with a spped of 27 km/h.As he approaches a circular turn
4. In Young’s double slit experiment, the intensity of light coming from the first slit
5. If oxygen has root mean square velocity of C m/s, then root mean square velocity of H

Topics: Motion in Straight Line (93)
Subject: Physics (2479)

---

Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score

18000+ students are using NEETLab to improve their score. What about you?

Solve Previous Year MCQs, Mock Tests, Topicwise Practice Tests, Identify Weak Topics, Formula Flash cards and much more is available in NEETLab Android App to improve your NEET score.

---

Share this page with your friends