Ask a Doubt
Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 9 Answered

A car of mass 1000 kg is moving with a certain speed when a constant braking force of 1000 N acts on it for 5 seconds and the speed of the car reduces to half its original speed. Find the further time required to stop the car if the same braking force acts.
Asked by rachitraj152007 | 03 Jan, 2021, 07:10: PM
answered-by-expert Expert Answer
Retardation = breaking force / mass = 1000 N/ 1000 kg = 1 m/s2 
 
Let us use the following equation of motion to get intial speed u from known retardation a
 
v = u - (a × t ) ...................(1)
 
where u is initial speed,  v is speed after t seconds and a is retardation. 
 
Since after 5 seconds , speed is reduced to half, then we have
 
( u/2 ) = u - ( 1 × 5 )   or  we get  initial speed u = 10 m/s
 
speed after 5 seconds = (10 / 2 ) = 5 m/s
 
time require to stop completely is determined from eqn.(1) by substituting final speed v = 0 and initial speed u = 5 m/s
 
0 = 5 - (1 × t )   or  time to stop the vehicle , t = 5 s
Answered by Thiyagarajan K | 03 Jan, 2021, 07:31: PM

Application Videos

Concept Videos

Multiple Choice Questions Practice Test Subjective Questions Webinar Subjective Questions Pre Board Assessment
Answered Unanswered My Questions My Answers
CBSE 9 - Physics
Which of the following is more compressible sand clay or dough
Asked by indrajeetghogare | 04 Jun, 2023, 01:44: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
if u is an initial velocity v is final velocity of body and t is time taken by boddy to attain a velocity from u to v then find the value of acceleration A
Asked by Anushkamishra385123 | 14 May, 2023, 12:39: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
can velocity be constant with acceleration?
Asked by adityatripathi84418 | 02 May, 2023, 10:29: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
A boy throws a steel ball straight up. Consider the motion of the ball only after it has left the boy's hand but before it touches the ground and assume that forces exerted by the air are negligible. For these conditions, the force(s) acting on the ball is (are): a. A downward force of gravity along with a steadily decreasing upward force b. A steadily decreasing upward force from the moment it leaves the boy's hand until it reaches its highest point on the way down there is a steadily increasing downward force of gravity as the object gets closer to the earth c. Constant downward force of gravity along with an upward force that steadily decreases until the ball reaches it highest point on the way down there is only a constant downward force of gravity d. Constant downward force of gravity only
Asked by harshsrivastava8896606 | 17 Apr, 2023, 01:47: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
For electric power transmission, copper or aluminium wire is used?
Asked by pramilam | 18 Mar, 2023, 08:54: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
What is the SI Unit of "Intensity of Sound"?
Asked by manaskumarbiswasbrb | 04 Feb, 2023, 08:35: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
explain human ear with lable diagram
Asked by sm6878261 | 12 Jan, 2023, 07:42: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
What is sound 
Asked by ahirejay2020 | 07 Jan, 2023, 10:41: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
why pressure increases with depth in fluid
Asked by sknv159357 | 05 Jan, 2023, 08:29: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 9 - Physics
An object starts from rest and travels 20m in first 2 s and 160 m in 4 s . Find its velocity 7 s after the start .
Asked by asyadav1230 | 20 Dec, 2022, 07:17: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
My Class Videos Tests ₹ Plans Ask a Doubt