8th Science Refresher course Topic 3 - Answer key
Lesson 3 - Force and Motion - Refresher course Answer
EVALUATION
1. Choose the correct answer
1. The average speed of a car which travels 60 km in 3 hours
(a ) 10 km / h
(b ) 20 km / h
( c ) 30 km / h
(d ) 60 km / h
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2. How the speed differs from velocity
(a) speed is velocity in a given direction
(b) velocity is speed in a given direction
(c) They are the same
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3. A car moves 80 km to the south, what is its displacement
(a) 20km south
(b) 50km east
(c) 80km south
(d) 160km north
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4. A particle moves in a circular path of radius “r“ ,what is the displacement of the particle
after passing half of the circular path
(a) zero
(b) r
(c) 2r
(d) r/2
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5.Acceleration is the measure of the change in ----------
(a) density
(b) motion
(c) velocity
(d) mass
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II. Fill in the blanks
1. Minimum distance between the two places in straight line path ----------
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2. The rate of change of velocity ---------------- .
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3. It he velocity of a particle increases with respect to time, it gets ------------- acceleration.
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4. In Speed—Time graph, the slope line gives ---------. value.
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5. SI unit of velocity is --------------.
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6. The negative acceleration is called as ------------------.
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7. Speed is a ---------- quantity.
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8. Velocity has ----------- value and ---------- value .
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9. Distance is ------------ measurement.
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10. SI unit of acceleration is --------------- .
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III. Match the following
1. Displacement-a = (v- u ) / t
2. Speed- Uniform velocity
3. Acceleration- Metre (m)
4. Velocity - Distance / Time
5. Speed of light in vaccum -Displacement / Time
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