Question:
What conclusion do you draw when displacement-time graph of a body is as shown in Fig.?
Answer:
The body is moving with a uniform velocity.
Motion
Q 1.
Derive graphically the equation of motion for position-velocity relation of a body moving with uniform acceleration.
Q 2.
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 3.
A body starts from rest.What is zero ?
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.
In addition to speed,what else should be known to predict the position of a moving body from a given starting point ?
Q 6.
What can you calculate from speed-time graph of a body ?
Q 7.
Under what conditions(s) is the magnitude of average
Q 8.
What is represented by the graphs in Fig.?
.
Q 9.
What is the relationship between the buoyant force on an object and the liquid displaced by it ?
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.
Relative density of silver is 10.8.The density of water is
.What is the density of silver in SI units ?
Q 12.
An electric train is moving with a velocity of 120 km/h. How much distance will it move in 30 s ?
Q 13.
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 14.
Name the quantity that represents rate of change of velocity ?
Q 15.
The density of turpentine oil is
.What will be its relative density ?
Q 16.
Why does a person feel pain when he stands on a pile of gravel than when he stands on a bed of sand ?
Q 17.
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 18.
What does the path of an object look like when it is in uniform motion?
Q 19.
When will you say a body is in (i) uniform acceleration? (ii) nonuniform acceleration?
Q 20.
What does the slope of distance-time graph indicate?
Q 21.
What will be the initial velocity of an object under free fall?
Q 22.
What are the values of distance travelled and displacement in covering 10 m from P to Q and coming back ?
Q 23.
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 24.
Why is a slight blow on a cork of bottle fully filled with a liquid sufficient to break the bottle ?
Q 25.
Distinguish between speed and velocity.
Q 26.
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 27.
What can you say about the motion of an object whose distance-time graph is a straight line parallel to the time axis ?
Q 28.
A particle moves over three quarters of a circle of radius r.What is the magnitude of its displacement ?
Q 29.
Use graphical method to derive the relation
-
= 2 as,where the symbols have their usual meanings.
Q 30.
Write the three equations of uniformly accelerated motion. Give the meaning of each symbol in them.
Q 31.
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 32.
Why is it easier to swim in sea water than in river water ?
Q 33.
The speed-time graph for a car is shown is figure below.
(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 the period.
(b) Which part of the graph represents uniform motion of the car?
Q 34.
Name the terms represented by various symbols in the equation, v = u + at.
Q 35.
What is thrust ?How is it related to pressure ? Give their units.
Q 36.
A scalar quantity has ?
(a) magnitude only
(b) direction only
(c) both direction and magnitude
(d) none of these
Q 37.
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 38.
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 39.
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 40.
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 41.
Under what condition(s) is the magnitude of average velocity of an object equal to its average speed?
Q 42.
A car accelerates uniformly from 18 km/h to 36 km/h in 5 second. Calculate (i) the acceleration and (ii)the distance covered by the car in that time.
Q 43.
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 44.
What conclusion do you draw when displacement-time graph of a body is as shown in Fig.?
Q 45.
Explain the terms : uniform motion and non-uniform motion with examples.
Q 46.
Draw speed-time graph for a body (i) at rest (ii) in uniform motion (iii) in uniformly accelerated motion.Discuss the results briefly.
Q 47.
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 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.
Why Is it difficult to hold a school bag having strap made of thin and strong string ?
Q 50.
A bus decreases its speed from 80 km/h to 60 km/h in 5 s. Find the acceleration of the bus.
