Question:
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 ?
Motion
Q 1.
Derive graphically the equation of motion for position-velocity relation of a body moving with uniform acceleration.
Q 2.
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 3.
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 4.
What can you calculate from speed-time graph of a body ?
Q 5.
A body thrown vertically upwards reaches a maximum height h.It then returns to ground.Calculate the distance travelled and the displacement.
Q 6.
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 7.
When will you say a body is in (i) uniform acceleration? (ii) nonuniform acceleration?
Q 8.
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 9.
Why is it easier to swim in sea water than in river water ?
Q 10.
What does the path of an object look like when it is in uniform motion?
Q 11.
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 12.
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 13.
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 14.
Explain the terms : uniform motion and non-uniform motion with examples.
Q 15.
Are motion and rest absolute or relative? Explain with an example.
Q 16.
Distinguish between speed and velocity.
Q 17.
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 18.
The density of turpentine oil is
.What will be its relative density ?
Q 19.
Why does a person feel pain when he stands on a pile of gravel than when he stands on a bed of sand ?
Q 20.
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 21.
What does the odometer of an automobile measure?
Q 22.
Fill in the blanks :
The rate of change of velocity of a moving body with time is called ______.
Q 23.
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 24.
In addition to speed,what else should be known to predict the position of a moving body from a given starting point ?
Q 25.
A particle moves over three quarters of a circle of radius r.What is the magnitude of its displacement ?
Q 26.
What is represented by the graphs in Fig.?
.
Q 27.
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 28.
Why is a slight blow on a cork of bottle fully filled with a liquid sufficient to break the bottle ?
Q 29.
A particle moves along the x axis from A to B. Which Of the following values of the initial and final coordinates, which results in a negative displacement?
(a) A = 4m, B = 6m
(b) A = −4m, B = −2m
(c) A = −4m, B = −8m
(d) A = −4m, B = 2m
Q 30.
What does the slope of distance-time graph indicate?
Q 31.
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 32.
Under what conditions(s) is the magnitude of average
Q 33.
Can displacement and distance ever be equal ?
Q 34.
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 35.
What is meant by scalars and vectors?
Q 36.
A scalar quantity has ?
(a) magnitude only
(b) direction only
(c) both direction and magnitude
(d) none of these
Q 37.
Fill in the blanks :
If the position of an object does not change with time, it is said to be at _____.
Q 38.
What can you say about the motion of an object whose distance-time graph is a straight line parallel to the time axis ?
Q 39.
What do the graphs shown in Fig.indicate?
Q 40.
Use graphical method to derive the relation
-
= 2 as,where the symbols have their usual meanings.
Q 41.
Why are sleepers used below the rails ?
Q 42.
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 43.
A body starts rolling over a horizontal surface with an initial velocity of 0.5
.Due to friction,its velocity decreases at the rate of 0 05
.How much time will it take for the body to stop ?
Q 44.
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 45.
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 46.
What is the relationship between the buoyant force on an object and the liquid displaced by it ?
Q 47.
An object has moved through a distance. Can it have zero displacement? If yes, support your answer with an example.
Q 48.
Under what condition(s) is the magnitude of average velocity of an object equal to its average speed?
Q 49.
What will be the initial velocity of an object under free fall?
Q 50.
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.
