Question:
In the above question,calculate
(i) distance travelled from O to A.
(ii) distance travelled from B to C.
(iii) total distance travelled by the body in 16 sec.
Answer:
(i) 12 m ; (ii)18 m ;(iii) 66 m
Motion
Q 1.
A farmer moves along the boundary of a square field of side 10 m in 40 s. What will be the magnitude of displacement of the farmer at the end of 2 minutes 20 seconds?
Q 2.
Derive graphically the equation of motion for position-velocity relation of a body moving with uniform acceleration.
Q 3.
A cyclist cycles for t second at a speed of 3 m/s and then for the same time at a speed of 5 m/s along a straight road due north. What is the average speed of the cyclist?
Q 4.
Calculate the greatest and the least pressure exerted by a metal block of size 20 cm x 8 cm x 5 cm and having a mass of 5 kg.
Q 5.
A farmer moves along the boundary of a square field of side 10 m in 40 s.What will be the magnitude of displacement of the farmer at the end of 2 minutes 20 seconds ?
Q 6.
A body starts from rest.What is zero ?
Q 7.
When will you say a body is in (i) uniform acceleration? (ii) nonuniform acceleration?
Q 8.
Why does a person feel pain when he stands on a pile of gravel than when he stands on a bed of sand ?
Q 9.
The mass of an empty 40 litre petrol tank of a vehicle is 8.0 kg.What will be its mass when filled completely with a fuel of density 700
Q 10.
Why is a slight blow on a cork of bottle fully filled with a liquid sufficient to break the bottle ?
Q 11.
Under what conditions(s) is the magnitude of average
Q 12.
Name the quantity that represents rate of change of velocity ?
Q 13.
What is the relationship between the buoyant force on an object and the liquid displaced by it ?
Q 14.
What will be the initial velocity of an object under free fall?
Q 15.
A particle moves over three quarters of a circle of radius r.What is the magnitude of its displacement ?
Q 16.
Explain the terms : uniform motion and non-uniform motion with examples.
Q 17.
The density of turpentine oil is
.What will be its relative density ?
Q 18.
Air is a fluid and our bodies displace air.As a result of this,a buoyant force is acting on each one of us.
(a)What is the approximate density of your body ?
(b) What is your approximate volume ?
(c) Estimate the magnitude of the buoyant force on you due to the air displaced.Consider your mass to be 75 kg.
(d)Does it mean that your weight is more than the scale reading ?
(Given density of air,pa =
)
Q 19.
Name the terms represented by various symbols in the equation, v = u + at.
Q 20.
Relative density of silver is 10.8.The density of water is
.What is the density of silver in SI units ?
Q 21.
What is represented by the graphs in Fig.?
.
Q 22.
Write the three equations of uniformly accelerated motion. Give the meaning of each symbol in them.
Q 23.
An electric train is moving with a velocity of 120 km/h. How much distance will it move in 30 s ?
Q 24.
Why are sleepers used below the rails ?
Q 25.
What does the slope of distance-time graph indicate?
Q 26.
In addition to speed,what else should be known to predict the position of a moving body from a given starting point ?
Q 27.
What is the relation between true weight,apparent weight and the loss in weight of a body immersed in a fluid ? Give some practical applications of Archimedes’Principle.
Q 28.
What does the path of an object look like when it is in uniform motion?
Q 29.
Fill in the blanks :
The rate of change of velocity of a moving body with time is called ______.
Q 30.
What can you say about the motion of an object whose distance-time graph is a straight line parallel to the time axis ?
Q 31.
What is meant by scalars and vectors?
Q 32.
A car travels along a straight line for first half time with speed 40 km/h and the second half time with speed 60 km/h. Find the average speed of the car.
Q 33.
Use graphical method to derive the relation
-
= 2 as,where the symbols have their usual meanings.
Q 34.
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 35.
What are the values of distance travelled and displacement in covering 10 m from P to Q and coming back ?
Q 36.
A weather forecasting plastic balloon of volume
contains hydrogen of density
.The mass of the empty balloon is 7.15 kg.Calcuiate (a) the mass or 'hydrogen in the balloon (b) Tne mass of balloon filled with hydrogen.
Q 37.
Why is it easier to swim in sea water than in river water ?
Q 38.
A ship is moving at a speed of 56 km/h.One second later,it is moving at 58 km/h.What is its acceleration ?
Q 39.
What can you calculate from speed-time graph of a body ?
Q 40.
What is thrust ?How is it related to pressure ? Give their units.
Q 41.
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 42.
When will you say a body is in (») uniform acceleration ? (ii) non-uniform acceleration ?
Q 43.
The speed-time graph for a car is shown is Fig.
(a) Find how far does the car travel in the first 4 seconds.Shade the area on the graph that represents the distance travelled by the car during this period.
(b) Which part of the graph represents uniform motion of the car ?
.
Q 44.
An artificial satellite is moving in a circular orbit of radius 42250 km. Calculate its speed if it takes 24 hours to revolve around the Earth.
Q 45.
What conclusion do you draw when displacement-time graph of a body is as shown in Fig.?
Q 46.
A block of wood is kept on a table top.The mass of the wooden block is 5 kg and its dimensions are 40 cm x 20 cm x 10 cm.Find the pressure exerted by the wooden block on the table top if it is made to lie on the table with its sides of dimensions (a) 20 cm x 10 cm (b) 40 cm x 20 cm. Given g =
.
Q 47.
A solid body of mass
kg and volume
is put in water.Will the body float or sink ?
Q 48.
An object weighs 9.8 N in air and 9.0 N when fully immersed in water.How much is the buoyant force on the object ?
Q 49.
State Archimedes’ Principle ? What is the relation between true weight,apparent weight and the buoyant force ?
Q 50.
Human corpse always floats on the surface of water,but the head always stays within water.Why ?
