## Physics - Motion

Class-IX

Assignment Sheet

**Q1(MCQs) : Choose the correct option from choices given.**

ⅰ A particle is moving in a circular path of radius’ r’. The displacement after half a circle would be

(a) Zero

(b) π × r

(c) 2r

(d) 2 × π × r

ⅱ The numerical ratio of displacement and distance of a moving object is

(a) always greater than 1.

(b) always equal to 1.

(c) always more than 1.

(d) equal or less than 1.

ⅲ An object has moved through a finite distance

(a) its displacement must be equal to the distance moved by it.

(b) its displacement must be positive .

(c) its displacement is less than the distance moved by it.

(d) Displacement may be zero.

ⅳ Speedometer fitted in an automobile measure its

(a) average speed

(b) acceleration

(c) instantaneous speed

(d) distance covered

ⅴ An object is said to have a variable velocity if

(a) its speed changes

(b) its direction of motion changes

(c) its speed as well as direction of motion changes.

(d) all of the above

**Q2: Answer the following in brief.**

**(a)**The distance time graph of a particle is a straight line parallel to the time axis, it means that the

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**(b)**What is the value of acceleration for a body at rest?

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**(c)**Odometer is an instrument fitted in an automobile measures

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**(d)**A student considered Earth as point object while considering its motion around the sun, Is he justified?

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**(e)**What is real meaning of negative acceleration?

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**Q3**:

ⅰ Draw the graphical representation of motion(on graph paper)

(a) Uniform speed

(b) Non uniform speed

ⅱ Draw the Speed-time graphs for the following:

a) When velocity remains constant

b) Uniform acceleration

c) When initial speed of a body is not zero.

d) Non uniform acceleration

**Q4**: A car is moving on a straight road with uniform acceleration. The following table gives the speed of the car at various instants of time:

┌───────┬───┬───┬───┬───┬───┬───┬───┐ │ Speed │5 │10 │15 │20 │25 │30 │35 │ ├───────┼───┼───┼───┼───┼───┼───┼───┤ │ Time │0 │10 │20 │ 30│ 40│50 │60 │ └───────┴───┴───┴───┴───┴───┴───┴───┘Draw the speed time graph by choosing a convenient scale. Determine for it:

(a) The acceleration of the car

(b) The distance travelled by the car in 60 seconds?

**Q5: Write the differences between:**

(a) Distance vs Displacement

(b) Speed vs Velocity

**Q6**: An object starting from rest covers 20 metres in first 2 seconds & 160 metres in next 4 seconds. What is its velocity after 7 seconds from the start?

**Q7**: A car moving at speed of 72km/h and applies brakes which provide a retardation of 5m/s².

ⅰ How much time does the car take to stop?

ⅱ How much distance does the car cover before coming to rest?

ⅲ What would be the stopping distance needed if speed of the car is doubled?

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