12th Grade > Physics
MOTION IN TWO DIMENSION MCQs
Total Questions : 31
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Answer: Option B. -> t1t2 α R
:
B
For same range angles of projection should be θ and 90 - θ
So, time of flights t1 = 2usinθg and
t2 = 2usin(90−θ)g = 2ucosθg
By multiplying = t1t2 = 4u2sinθcosθg2
t1t2 = 2g (u2sin2θ)g = 2Rg ⇒ t1t2 α R
:
B
For same range angles of projection should be θ and 90 - θ
So, time of flights t1 = 2usinθg and
t2 = 2usin(90−θ)g = 2ucosθg
By multiplying = t1t2 = 4u2sinθcosθg2
t1t2 = 2g (u2sin2θ)g = 2Rg ⇒ t1t2 α R
Answer: Option C. -> √v2+g2t2−(2vsinθ)gt
:
C
Instantaeous speed of rising mass after t sec will be vt = √vx2+vy2
where vx = v sin θ = Horizontal component of velocity
vy = v sin θ - gt = Vertical component of velocity
vt = √(vcosθ)2+(vsinθ−gt)2
:
C
Instantaeous speed of rising mass after t sec will be vt = √vx2+vy2
where vx = v sin θ = Horizontal component of velocity
vy = v sin θ - gt = Vertical component of velocity
vt = √(vcosθ)2+(vsinθ−gt)2
Question 3. An aeroplane is flying at a constant horizontal velocity of 600 km/hr at an elevation of 6 km towards a point directly above the target on the earth's surface. At an appropriate time, the pilot releases a ball so that it strikes the target at the earth. The ball will appear to be falling
Answer: Option C. -> On a parabolic path as seen by an observer on the ground near the target
:
C
The pilot will see the ball falling in straight line because the reference frame is moving with the same horizontal velocity but the observer at rest will see the ball falling in parabolic path.
:
C
The pilot will see the ball falling in straight line because the reference frame is moving with the same horizontal velocity but the observer at rest will see the ball falling in parabolic path.
Answer: Option B. -> To fall at an angle going from west to east
:
B
A man is sitting in a bus and travelling from west to east, and the rain drops are appears falling vertically down.
vm = velocity of man
vr = Actual velocity of rain which is falling at an angle θ with vertical
vrm = velocity of rain w.r.t to moving man
If the another man observe the rain then he will find that actually rain falling with velocity v, at an angle going from west to east.
:
B
A man is sitting in a bus and travelling from west to east, and the rain drops are appears falling vertically down.
vm = velocity of man
vr = Actual velocity of rain which is falling at an angle θ with vertical
vrm = velocity of rain w.r.t to moving man
If the another man observe the rain then he will find that actually rain falling with velocity v, at an angle going from west to east.
Answer: Option B. -> R1 < R2
:
B
Reaction on inner wheel R1 = 12M[g - v2hra]
Reaction on outer wheel R2 = 12M[g + v2hra]
where, r = radius of circular path, 2a = distance between two wheels and h = height of centre of gravity of car
:
B
Reaction on inner wheel R1 = 12M[g - v2hra]
Reaction on outer wheel R2 = 12M[g + v2hra]
where, r = radius of circular path, 2a = distance between two wheels and h = height of centre of gravity of car
Answer: Option C. -> 3
:
C
Using relation θ = ω0t + 12 α t2
θ1 = 12 (α) 22 = 2 α ..(i) (As ω0=0,t=2sec)
Now using same question for t = 4 sec , ω0 = 0
θ1 + θ2 = 12 (4)2 = 8 α ..(ii)
From (i) and (ii), θ1 = 2 α and θ2 = 6α ∴ θ1θ2 = 3
:
C
Using relation θ = ω0t + 12 α t2
θ1 = 12 (α) 22 = 2 α ..(i) (As ω0=0,t=2sec)
Now using same question for t = 4 sec , ω0 = 0
θ1 + θ2 = 12 (4)2 = 8 α ..(ii)
From (i) and (ii), θ1 = 2 α and θ2 = 6α ∴ θ1θ2 = 3