Question:
What are the values of distance travelled and displacement in covering 10 m from P to Q and coming back ?
Answer:
Distance travelled = 10 m + 10 m = 20 m
displacement = zero.
Motion
Q 1.
Derive graphically the equation of motion for position-velocity relation of a body moving with uniform acceleration.
Q 2.
What can you calculate from speed-time graph of a body ?
Q 3.
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 4.
Mathematically prove that the distance (S) travelled by an object is the average mean of initial velocity(u) and final velocity(v) having constant acceleration(a) in the direction of motion in a straight line.
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.
Distinguish between speed and velocity.
Q 7.
Under what conditions(s) is the magnitude of average
Q 8.
Why is it easier to swim in sea water than in river water ?
Q 9.
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 10.
When will you say a body is in (i) uniform acceleration? (ii) nonuniform acceleration?
Q 11.
Are motion and rest absolute or relative? Explain with an example.
Q 12.
What does the path of an object look like when it is in uniform motion?
Q 13.
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 14.
What is represented by the graphs in Fig.?
.
Q 15.
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 16.
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 17.
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 18.
Can displacement and distance ever be equal ?
Q 19.
A particle moves over three quarters of a circle of radius r.What is the magnitude of its displacement ?
Q 20.
Puja and Neha are close friends.Puja is a science graduate and Neha is a commerce graduate.Puja finds that while driving on a clear highway,Neha often exceeds the speed limit and agrues that there is no harm in doing so when the road is clear.Puja does not agree with her and tells her that with increase in speed, stopping distance of car would increase and she would not be able to manage things if some stray cattle etc. appears suddenly on the way.Read the above passage and answer the following questions :
(i) Is Puja right in her statement?
(ii) What values are displayed by Puja in her statement?
(iii) How is stopping distance related to speed of vehicle?
Q 21.
A force of 16 N is distributed uniformly on one surface of a cube of edge 8 cm.Find the pressure on this surface.
Q 22.
The density of turpentine oil is
.What will be its relative density ?
Q 23.
A train is running at a speed of 72 km/h. It crosses a bridge of length half kilometer in 1 minute. Calculate the length of the train.
Q 24.
What does the slope of distance-time graph indicate?
Q 25.
A scalar quantity has ?
(a) magnitude only
(b) direction only
(c) both direction and magnitude
(d) none of these
Q 26.
What do the graphs shown in Fig.indicate?
Q 27.
Draw speed-time graph for a body (i) at rest (ii) in uniform motion (iii) in uniformly accelerated motion.Discuss the results briefly.
Q 28.
Why is a slight blow on a cork of bottle fully filled with a liquid sufficient to break the bottle ?
Q 29.
Why are sleepers used below the rails ?
Q 30.
An object has moved through a distance. Can it have zero displacement? If yes, support your answer with an example.
Q 31.
A racing car has a uniform acceleration of 4
.What distance will it cover in 10 s after start ?
Q 32.
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 33.
What conclusion do you draw when displacement-time graph of a body is as shown in Fig.?
Q 34.
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 35.
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 36.
The mass of a density bottle is 25 g when empty, 50 g when filled completely with water and 365 g when filled completely with mercury. Find the density of mercury.
Q 37.
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 38.
A body thrown vertically upwards reaches a maximum height h.It then returns to ground.Calculate the distance travelled and the displacement.
Q 39.
A train 100 m long moving on a straight level track passes a pole in 5 s. Find (a) the speed of the train (b) the time it will take to cross a bridge 500 m long.
Q 40.
A trolley, while going down an inclined plane, has an acceleration of
starting from rest.What will be its velocity 3 s after the start ?
Q 41.
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 42.
Name the quantity that represents rate of change of velocity ?
Q 43.
In addition to speed,what else should be known to predict the position of a moving body from a given starting point ?
Q 44.
What remains constant in uniform circular motion ?
Q 45.
A body starts from rest.What is zero ?
Q 46.
Name the terms represented by various symbols in the equation, v = u + at.
Q 47.
Write the three equations of uniformly accelerated motion. Give the meaning of each symbol in them.
Q 48.
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 49.
Discuss three important practical aspects of pressure related to daily life.
Q 50.
What is Archimedes’ Principle ? How can it be experimentally verified ?
