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Chapter 8 : Motion/Class IX
Students are welcome to ask question related to chapter 8/class ix.
Please write your question or simply question number in coment section
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Chapter 8 : Motion/Class IX
Students are welcome to ask question related to chapter 8/class ix.
Please write your question or simply question number in coment section
Office:Silver Plaza, Opposite Kabir Colony , Anoop Shaher Road, Jamalpur Aligarh-202002, U.P-India
Contact Number: +91-7302066066
e-mail id : qacademyaligarh@gmail.com
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72
ReplyDeleteAns: 72 (c)
ReplyDeleteu = -50m/s
g= 10m/s2
let “t” be the time taken to reach maximum height,then
v = u +at
0 = 50 +(-10)t
t =5sec
the body will move in upward direction from 0n to 5th sec and the move I downward directon from 6th to 10th sec.
Ans is (c)
Mohd Qasim
ReplyDeleteQues.26 ,force and law of motion.
Ques,In fig below, when the...............
...placed over it
26: Ans :(a)
DeleteThe coin tries to remain its position due to inertia of rest while the card moves from its position when it is flicked by figure, so the coin moves down.
Mohd. Qasim
ReplyDeleteQues.41 A force of 10 Newton ....
....starts from rest.
Ans: (c)
DeleteF=10N; m=2kg; t= 5s; u= 0
a= F/m=10/2=5m/s2
v = u +at = 0+5x5 = 25m/s
Change in momentum = (mv-mu) = m(v-u) = 2x(25-0) = 50kgm/s
Mohd Qasim
ReplyDeleteQues .42 .A force of 10 Newton...
....force act on the body
Ans:(d) 4 seconds
DeleteF=10N, m=2kg, initial momentum(pi) = 10kg/s, Final momentum( pf) = 50kgm/s, t =?
F = (pf-pi)/t t = (pf-pi)/F = (50 - 10)/10 = 4s
Mohd Qasim
ReplyDeleteQues.43.which of the following is Incorrect statement.
a) The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of force.
DeleteF = rate of change of momentum, so it is correct
b) The change of momentum of an object is equal to the applied unbalanced force in the direction of force.
Force = change in momentun /time ==> Chaneg in monentum = Force x time....option (b) is incorrect
c) The force acting on an object can be calculated as a product of its mass and acceleration
F= mass x acceleration so it is correct
Mohd Qasim
ReplyDeleteQues.53.A car is moving with a speed of 72km/hr .................passenger is 1000kg.
Ans (d) 2000N
ReplyDeleteu= 72km/hr = 72 x (5/18) = 20m/s, v = 0 , t= 10s, m = 1000kg
v = u + at == > a = (v – u)/t = (0 – 20)/ 10 = -2m/s2
F= ma= 1000 x (-2) = -2000N, the magnitude of force = 2000N