Question:
What does the slope of distance-time graph indicate?
Answer:
Slope indicates the speed of the object.
Motion
Q 1.
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 2.
Derive graphically the equation of motion for position-velocity relation of a body moving with uniform acceleration.
Q 3.
What can you calculate from speed-time graph of a body ?
Q 4.
When will you say a body is in (i) uniform acceleration? (ii) nonuniform acceleration?
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 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 7.
A body starts from rest.What is zero ?
Q 8.
Why is it easier to swim in sea water than in river water ?
Q 9.
Why does a person feel pain when he stands on a pile of gravel than when he stands on a bed of sand ?
Q 10.
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 11.
What is represented by the graphs in Fig.?
.
Q 12.
Distinguish between speed and velocity.
Q 13.
Can displacement and distance ever be equal ?
Q 14.
In addition to speed,what else should be known to predict the position of a moving body from a given starting point ?
Q 15.
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 16.
Under what conditions(s) is the magnitude of average
Q 17.
What are the values of distance travelled and displacement in covering 10 m from P to Q and coming back ?
Q 18.
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 19.
What does the odometer of an automobile measure?
Q 20.
What does the path of an object look like when it is in uniform motion?
Q 21.
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 22.
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 23.
Relative density of silver is 10.8.The density of water is
.What is the density of silver in SI units ?
Q 24.
The density of turpentine oil is
.What will be its relative density ?
Q 25.
The equation v = u + at 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 26.
A body thrown vertically upwards reaches a maximum height h.It then returns to ground.Calculate the distance travelled and the displacement.
Q 27.
Write the three equations of uniformly accelerated motion. Give the meaning of each symbol in them.
Q 28.
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 29.
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 30.
What will be the initial velocity of an object under free fall?
Q 31.
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 32.
An electric train is moving with a velocity of 120 km/h. How much distance will it move in 30 s ?
Q 33.
Is distance a vector quantity ?
Q 34.
A particle moves over three quarters of a circle of radius r.What is the magnitude of its displacement ?
Q 35.
Use graphical method to derive the relation
-
= 2 as,where the symbols have their usual meanings.
Q 36.
Draw speed-time graph for a body (i) at rest (ii) in uniform motion (iii) in uniformly accelerated motion.Discuss the results briefly.
Q 37.
An iron sphere is suspended with a spring.The length of the spring increases.When the sphere is completely in water,the extension in the length of the spring decreases.Why does it happen so ?
Q 38.
Why are sleepers used below the rails ?
Q 39.
An object has moved through a distance. Can it have zero displacement? If yes, support your answer with an example.
Q 40.
A bus decreases its speed from 80 km/h to 60 km/h in 5 s. Find the acceleration of the bus.
Q 41.
A scooter acquires a velocity of 36 km/h in 10 seconds just after the start.Calculate the acceleration of the scooter.
Q 42.
What can you say about the motion of an object whose distance-time graph is a straight line parallel to the time axis ?
Q 43.
Name the terms represented by various symbols in the equation, v = u + at.
Q 44.
What conclusion do you draw when displacement-time graph of a body is as shown in Fig.?
Q 45.
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 46.
Why is a slight blow on a cork of bottle fully filled with a liquid sufficient to break the bottle ?
Q 47.
What is meant by buoyant force ? Describe an experiment to demonstrate the existence of this force.
Q 48.
Are motion and rest absolute or relative? Explain with an example.
Q 49.
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 50.
A scalar quantity has ?
(a) magnitude only
(b) direction only
(c) both direction and magnitude
(d) none of these
