JEE Questions for Physics Motion In A Straight Line Quiz 6 - MCQExams.com

The displacement x of a particle varies with time t,x = ae–αt + beβt, where a, b, α and β are positive constants. The velocity of the particle will
  • Go on decreasing with time
  • Be independent of α and β
  • Drop to zero when α = β
  • Go on increasing with time
A car moving with a velocity of 10 m/s can be stopped by the application of constant force F in a distance of 20 m. If the velocity of the car is 30 m/s, it can bestopped by this force in

  • Physics-Motion in a Straight Line-81600.png
  • 20 m
  • 60 m
  • 180 m
The displacement of a particle is given by y = a + bt + ct2– dt4. The initial velocity and acceleration are respectively.
  • b, –4d
  • –b, 2c
  • b, 2c
  • 2c, – 4d
A car moving with a speed of 40 km/hr. can be stopped by applying brakes after atleast 2 m. If the same car is moving with a speed of 80 km/hr., what is the minimum stopping distance
  • 8 m
  • 2 m
  • 4 m
  • 6 m
An elevator car, whose floor to ceiling distance is equal to 2.7 m, starts ascending with constant acceleration of 1.2 ms–2, 2 sec after the start, a bolt begins falling from the ceiling of the car. The free fall time of the bolt is
  • √0.54 s
  • √6 s
  • 0.7 s
  • 1 s
A particle moves along a straight line such that its displacement at any time t is given by
S = t3– 6t2 + 3t + 4 metres
The velocity when the acceleration is zero is
  • 3 ms–1
  • –12 ms–1
  • 42 ms–1
  • –9 ms–1
The position x of a particle with respect to time t along x–axis is given by x = 9t2–t3, where x is in metres and t in second. What will be the position of this particle when it achieves maximum speed along the +xdirection
  • 32 m
  • 54 m
  • 81 m
  • 24 m
If a body starts from rest and travels 120 cm in the 6thsecond, then what is the acceleration
  • 0.20 m/s2
  • 0.027 m/s2
  • 0.218 m/s2
  • 0.03 m/s2
If a car at rest accelerates uniformly to a speed of 144 km/hr. in 20 s. Then it covers a distance of
  • 20 m
  • 400 m
  • 1440 m
  • 2880 m
The position x of a particle varies with time t asx = at2–bt3. The acceleration of the particle will bezero at time t equal to

  • Physics-Motion in a Straight Line-81609.png
  • 2)
    Physics-Motion in a Straight Line-81610.png

  • Physics-Motion in a Straight Line-81611.png
  • Zero
A truck and a car are moving with equal velocity. On applying the brakes both will stop after certaindistance, then
  • Truck will cover less distance before rest
  • Car will cover less distance before rest
  • Both will cover equal distance
  • None of the above
If a train travelling at 72 kmph is to be brought to rest in a distance of 200 metres, then its retardation should be
  • 20 ms–2
  • 10 ms–2
  • 2 ms–2
  • 1 ms–2
The motion of a particle is described by the equation x = a + bt2, where a = 15 cm and b = 3 cm/s2. Its instantaneous velocity at time 3 sec will be
  • 36 cm/sec
  • 18 cm/sec
  • 16 cm/sec
  • 32 cm/sec
A body is moving according to the equation x = at + bt2– ct3, where x = displacement and a, b and c are constants. The acceleration of the body is
  • a + 2bt
  • 2b + 6ct
  • 2b –6ct
  • 3b – 6ct2
The distance travelled by a particle is proportional to the squares of time, then the particle travels with
  • Uniform acceleration
  • Uniform velocity
  • Increasing acceleration
  • Decreasing velocity
Acceleration of a particle changes when
  • Direction of velocity changes
  • Magnitude of velocity changes
  • Both of above
  • Speed changes

Physics-Motion in a Straight Line-81618.png
  • 24 metres
  • 12 metres
  • 5 metres
  • Zero
The average velocity of a body moving with uniform acceleration travelling a distance of 3.06 m is 0.34 ms–1. If the change in velocity of the body is 0.18 ms–1 during this time, its uniform acceleration is
  • 0.01 m/s2
  • 0.02 m/s2
  • 0.03 m/s2
  • 0.04 m/s2
Equation of displacement for any particle is s = 3t3 + 7t2 + 14t + 8m. Its acceleration at time t =1sec is
  • 10 m/s2
  • 16 m/s2
  • 25 m/s2
  • 32 m/s2
A body A starts from rest with an acceleration a1 . After 2 seconds, another body B starts from rest with an acceleration a2. If they travel equal distances in the 5th second, after the start of A, then the ratio a1 : a2 is equal to
  • 5 : 9
  • 5 : 7
  • 9 : 5
  • 9 : 7
The velocity of a bullet is reduced from 200 m/s to 100 m/s while travelling through a wooden block of thickness 10 cm. The retardation, assuming it to be uniform, will be
  • 10 × 104 m/s2
  • 12 × 104 m/s2
  • 13.5 × 104 m/s2
  • 15 × 104 m/s2
A body of 5 kg is moving with a velocity of 20 m/s. If a force of 100 N is applied on it for 10 s in the same direction as its velocity, what will now be the velocity of the body
  • 200 m/s
  • 220 m/s
  • 240 m/s
  • 260 m/s
A particle starts from rest, accelerates at 2 m/s2 for 10 s and then goes with constant speed for 30 s and then decelerates at 4 m/s2 till it stops. What is the distance travelled by it
  • 750 m
  • 800 m
  • 700 m
  • 850 m
The engine of a motorcycle can product a maximum acceleration 5 m/s2. Its brakes can produce a maximum retardation 10 m/s2. What is the minimum time in which it can cover a distance of 1.5 km
  • 30 sec
  • 15 sec
  • 10 sec
  • 5 sec
The path of a particle moving under the influence of a force fixed in magnitude and direction is
  • Straight line
  • Circle
  • Parabola
  • Ellipse
A particle moves a distance x in time t according to equation x = (t + 5)–1. The acceleration of particle is proportional to
  • (velocity)2/3
  • (velocity)3/2
  • (distance)2
  • distance)–2
A body travelling with uniform acceleration crosses two points A and B with velocities 20 ms–1 and 30 ms–1 and respectively. The speed of the body at the mid-point of A and B is nearest to
  • 25.5 ms–1
  • 25 ms–1
  • 24 ms–1
  • 22 ms–1
    Physics-Motion in a Straight Line-81627.png
Select the incorrect statements from the following
S1: Average velocity is path length divide by time interval.
S2 : In general, speed is greater than the magnitude of the velocity.
S3 : A particle moving in a given direction with a non-zero velocity can have zero speed.
S4: The magnitude of average velocity is the averagespeed.
  • S2 and S3
  • S1 and S4
  • S1, S3 and S4
  • All four statements

Physics-Motion in a Straight Line-81630.png

  • Physics-Motion in a Straight Line-81631.png
  • 2)
    Physics-Motion in a Straight Line-81632.png
  • 5 units
  • 9 units
The motion of a particle along a straight line is described by equation
x = 8 + 12t – t3
Where x is in metre and t in second. The retardation of the particle when its velocity becomes zero, is
  • 24 ms–2
  • Zero
  • 6 ms–2
  • 12 ms–2
0:0:1


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