| ⇦ | 
| ⇨ |
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: - The angle of a prism is A. One of its refracting surfaces is silvered
- A capacitor of 2.5 μF is charged through a resistor of 4 MΩ. In how much time
- A U²³⁵ reactor generates power at a rate of P producing 2×10⁸ fission per second.
- Moment of inertia, along the diameter of a ring is
- Two equal and opposite charges of masses m₁ and m₂ are accelerated
Topics: Motion in Straight Line
(93)
Subject: Physics
(2479)
Important MCQs Based on Medical Entrance Examinations To Improve Your NEET Score
- The angle of a prism is A. One of its refracting surfaces is silvered
- A capacitor of 2.5 μF is charged through a resistor of 4 MΩ. In how much time
- A U²³⁵ reactor generates power at a rate of P producing 2×10⁸ fission per second.
- Moment of inertia, along the diameter of a ring is
- Two equal and opposite charges of masses m₁ and m₂ are accelerated
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
Leave a Reply