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 particle moves over three quarters of a circle of radius r.What is the magnitude of its displacement ?

Q 4.

What is represented by the graphs in Fig.? .
  

Q 5.

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$kg/m3$

Q 6.

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 7.

Name the quantity that represents rate of change of velocity ?

Q 8.

Write the three equations of uniformly accelerated motion. Give the meaning of each symbol in them.

Q 9.

Why is a slight blow on a cork of bottle fully filled with a liquid sufficient to break the bottle ?

Q 10.

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 11.

A body starts from rest.What is zero ?

Q 12.

When will you say a body is in (i) uniform acceleration? (ii) nonuniform acceleration?

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.

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 15.

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 = $1.29\; kg/m3$)

Q 16.

Under what conditions(s) is the magnitude of average

Q 17.

What can you say about the motion of an object whose distance-time graph is a straight line parallel to the time axis ?

Q 18.

What is pressure in case of fluids ? What is Pascal’s law ?

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.

What will be the initial velocity of an object under free fall?

Q 21.

What conclusion do you draw when displacement-time graph of a body is as shown in Fig.?

Q 22.

Draw speed-time graph for a body (i) at rest (ii) in uniform motion (iii) in uniformly accelerated motion.Discuss the results briefly.

Q 23.

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 24.

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 25.

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 26.

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 27.

What is the relationship between the buoyant force on an object and the liquid displaced by it ?

Q 28.

Explain the terms : uniform motion and non-uniform motion with examples.

Q 29.

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 30.

A body thrown vertically upwards reaches a maximum height h.It then returns to ground.Calculate the distance travelled and the displacement.

Q 31.

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 32.

The density of turpentine oil is $840\; kg/m3$.What will be its relative density ?

Q 33.

Why is it easier to swim in sea water than in river water ?

Q 34.

A scalar quantity has ?
(a) magnitude only
(b) direction only
(c) both direction and magnitude
(d) none of these

Q 35.

The following is the distancc-time table of a moving car.
(a) Use a graph paper to plot the distance travelled by the car versus the time.
(b) When was the car travelling at the greatest speed ?
(c) What is the average speed of the car ?
(d) What is the speed between 11.25 am and 11-40 am ?
(e) During a part of the journey, the car was forced to slow down to 12 km/h.At what distance did this

Time	Distance
10.05 am 10.25 am 10.40 am 10.50 am 11.00 am 11.10 am 11.25 am 11.40 am	0 km 5 km 12km 22 km 26 km 28 km 38 km 42 km

Q 36.

When will you say a body is in (») uniform acceleration ? (ii) non-uniform acceleration ?

Q 37.

A trolley, while going down an inclined plane, has an acceleration of $2\; cm/s2$ starting from rest.What will be its velocity 3 s after the start ?

Q 38.

In addition to speed,what else should be known to predict the position of a moving body from a given starting point ?

Q 39.

What can you calculate from speed-time graph of a body ?

Q 40.

Using velocity time graph,establish the relation s = ut + $\frac{1}{2}$$at2$,where the symbols have their usual meanings.

Q 41.

A cube of edge length 10 cm is placed inside a liquid.The pressure at the centre of the face is 15 Pa.Find the force exerted by the liquid on this face.

Q 42.

A hydraulic automobile lift is designed to lift cars with a maximum mass of 3000 kg.The area of the piston carrying the load is $425\; cm2$.What maximum pressure would the smaller piston have to bear ?

Q 43.

Define pressure.What is its unit ?

Q 44.

What force acting on an area of $0.5\; m2$ will produce a pressure of 500 Pa ?

Q 45.

Pascal’s law states that a fluid in a confined space expands into every possible space if it is put under pressure.This law plays a very important role in our lives.Give three applications with brief description.

Q 46.

Under what condition(s) is the magnitude of average velocity of an object equal to its average speed?

Q 47.

Fill in the blanks :
The rate of change of velocity of a moving body with time is called ______.

Q 48.

A body travels a distance of 15 m from A to B and then moves a distance of 20 m at right angles to AB.Calculate the total distance travelled and the displacement.

Q 49.

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 50.

A body starts rolling over a horizontal surface with an initial velocity of 0.5 $m/s2$ .Due to friction,its velocity decreases at the rate of 0 05 $m/s2$.How much time will it take for the body to stop ?