Question:
in Fig, shows the distance-time graph of three objects A, B and C. Study the graph and answer the following questions :
(a) Which of the three is travelling the fastest ?
(b)Are ail three ever at the same point on the road ?
(c) How far has C travelled when B passes A ?
(d) How far has B travelled by the time it passes C ?
Answer:
(a) As slope of distance-time graph represents speed of an object, therefore, as is clear from Fig, B has maximum speed, i.e.,the object B moves the fastest.
(b) For meeting at any point on the road,the respective distance and time values must be same for all the three objects at that point. As the three lines do not meet at a single point, the three objects never meet on the road.
(c) As is clear from Fig , B passes A at D.At this Ume,C is at E,which corresponds to 7 km.Hence when B crosses A,then C is at 7 km from the origin.
(d) B crossed C at F at a distance of4.5 km from the origin.
Motion
Q 1.
The equation S = ut + ½at2 gives information as
(a) velocity is a function of time.
(b) velocity is a function of position.
(c) Position is a function of time.
(d) Position is function of velocity and time.
Q 2.
Fill in the blanks :
The rate of change of velocity of a moving body with time is called ______.
Q 3.
Are motion and rest absolute or relative? Explain with an example.
Q 4.
What do you mean by a body in rest?
Q 5.
Under what condition(s) is the magnitude of average velocity of an object equal to its average speed?
Q 6.
Which of the following is true for displacement?
(a) It cannot be zero.
(b) Its magnitude is greater than the distance travelled by the object.
Q 7.
Fig (below) shows the distance-time graph of three objects A,B and C. Study the graph and answer the following questions:
(a) Which of the three is travelling the fastest?
(b) Are all three ever at the same point on the road?
(c) How far has C travelled when B passes A?
(d) How far has B travelled by the time it passes C?
Q 8.
A bus decreases its speed from 80 km/h to 60 km/h in 5 s. Find the acceleration of the bus.
Q 9.
A racing car has a uniform acceleration of 4 m s–2.
What distance will it cover in 10 s after start?
Q 10.
What is the average velocity over the “round trip” of an object that is thrown straight up from the ground and falls straight back down to the ground?
Q 11.
Which of the following is true for displacement ?
(a) It cannot be zero.
(b) Its magnitude is greater than the distance travelled by the object.
Q 12.
What does the slope of distance-time graph indicate?
Q 13.
Calculate the mass of air enclosed in a room of length,breadth and height equal to 5 m, 3 m and 4 m respectively.Density of air =
.
Q 14.
Distinguish between speed and velocity.
Q 15.
(a)
Which human virtue was at stake when Archimedes came out with his principle while bathing in a tub ?
(b) Briefly discuss three cases where Archimedes Principle is at work.
Q 16.
What is the acceleration of a body moving with uniform velocity ?
Q 17.
When will you say a body is in (i) uniform acceleration? (ii) nonuniform acceleration?
Q 18.
A scalar quantity has ?
(a) magnitude only
(b) direction only
(c) both direction and magnitude
(d) none of these
Q 19.
What is locomotion ?
Q 20.
Derive graphically the equation of motion for position-velocity relation of a body moving with uniform acceleration.
Q 21.
Why do objects float or sink when placed on the surface of a liquid ?
Q 22.
A particle is moving in a circle of diameter 5 m. Calculate the distance covered and the displacement when it completes 3 revolutions.
Q 23.
A motor cycle moving with a speed of 5 m/s is subjected to an acceleration of 0.2
.Calculate the speed of the motor cycle after 10 second,and the distance travelled in this time.
Q 24.
What does the slope of a speed-time graph indicate ?
Q 25.
Explain what is meant by uniform circular motion.Give at least three examples.
Q 26.
What force acting on an area of
will produce a pressure of 500 Pa ?
Q 27.
Why do you feel lighter when you swim ?
Q 28.
What is Archimedes’ Principle ? How can it be experimentally verified ?
Q 29.
A body of 2.0 kg floats in a liquid.What is the buoyant force on the body ?
Q 30.
Human corpse always floats on the surface of water,but the head always stays within water.Why ?
Q 31.
What is meant by scalars and vectors?
Q 32.
A train travels some distance with a speed of 30 km/h and returns with a speed of 45 km/h.Calculate the average speed of the train.
Q 33.
Is displacement a scalar quantity ?
Q 34.
Convert a speed of 15 m/s into km/h
Q 35.
A hydraulic automobile lift is designed to lift cars with a maximum mass of 3000 kg.The area of the piston carrying the load is
.What maximum pressure would the smaller piston have to bear ?
Q 36.
The mass of a solid rectangular block of iron is 23.6 g and its dimensions are 2.1 cm x 1.2 cm x 1.1 cm.Calculate the density of iron.
Q 37.
A metallic sphere of radius 2.0 cm is completely dipped in water.Find the force of buoyancy on it.
Q 38.
A solid body of mass
kg and volume
is put in water.Will the body float or sink ?
Q 39.
A bus starting from rest moves with a uniform acceleration of 0.1 ms–2 for 2 minutes.
Find (a) the speed acquired, (b) the distance travelled.
Q 40.
Under what conditions(s) is the magnitude of average
Q 41.
A stone is thrown in a vertically upward direction with a velocity of 5 m/s. If the acceleration of the stone during its motion is
in the downward direction,what will be the height attained by the stone and how much time will it take to reach there ?
Q 42.
What is the SI unit of acceleration ?
Q 43.
A body starts from rest.What is zero ?
Q 44.
Define the term uniform acceleration.Give one example of uniformly accelerated motion.
Q 45.
Explain the terms : uniform motion and non-uniform motion with examples.
Q 46.
A stone tied to one end of a string is rotated in a circle.Explain what happens when the stone is released.
Q 47.
A force of 100 N is applied on an object of area
.Calculate the pressure.
Q 48.
Calculate the pressure when a force of 200 N acts on an
Q 49.
What does the path of an object look like when it is in uniform motion?
Q 50.
A train starting from a railway station and moving with uniform acceleration attains a speed 40 km/h in 10 minutes. Find its acceleration.
