MENU

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 Physics Question

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 tuning fork gives 4 beats with 50 cm length of a sonometer
  2. The dimensions of Planck’s constant is same as that of
  3. A parallel beam of fast moving electrons is incident normally on a narrow slit.
  4. A solenoid of length l metre has self inductance L henry. If number of turns
  5. In an ammeter, 0.2% of main current passes through the galvanometer

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.

NEETLab Mobile App

Share this page with your friends

Be the first to comment

Leave a Reply

Your email address will not be published.


*