Skip to content 1 Explain why roads on hills are built to wind around in gentle slopes rather than going straight up?
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2 Why is it easier to open the lid of a can by using a spoon as shown in Figure.[Pg. No. 135]
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3 To reach a higher floor, we find climbing an inclined ladder easier in comparison to climbing a vertical ladder.
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4 State whether True or False.
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5 Why do you push an object closer to scissors fulcrum when you want to cut an object which is hard?
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6 Throughout history, many designs of perpetual machines (using wheels, weights or magnets) have been proposed but none actually work.
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7 For each of the following situations, identify the energy transformation that takes place:
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8 A student is slowly lifted straight up in an elevator from the ground level to the top floor of a building.
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9 A crane lifts a mass m to the 10th floor of a building in a certain time.
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10 Fill in the blanks.
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11 When a ball thrown upwards reaches its highest point, which of the following statement(s) are correct?
MCQ (Multiple Choice)
12 On a seesaw with sliding seats, a child is sitting on one side and an adult on the other side.
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13 A man of mass 60 kg rides a scooter of mass 100 kg.
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14 A ball of mass 2 ~kg is thrown up with a velocity of 20 ~ms^-1.
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15 Which factors determine the energy required to raise a flag from the ground to the top of a tall flagpole using a pulley?
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16 A 10.0 kg block is moving on horizontal floor with negligible friction. As shown in the given figure a variable force is applied on the block in its direction of motion from its…
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17 The gravitational attraction on the surface of the Moon (lunar surface) is about 1/6th of that on the surface of the Earth.An astronaut can throw a ball up to a height of 8 m from…
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18 The potential energy-displacement graph of a 0.5 kg ball moving along a frictionless track is shown in the given figure. At O, the velocity of the ball is 0 ms⁻¹ and potential…
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19 A 1000 kg car is moving along a road at a constant speed.
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20 A coconut of mass 1.5 kg falls from the top of a coconut tree onto the wet sand on a beach. The height of the tree is 10 m. On impact, the coconut comes to rest by making a…
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21 What will be the magnitude of the velocity of the child at the bottom of the slide no.
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22 Will two children of different masses reach the bottom of the same slide with the same velocity?
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23 Which of the slides will result in the largest magnitude of velocity for the child at its bottom?[Pg. No. 116]
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24 Is the work done by friction on the stack of coins that travels on a rough surface (positive, negative or zero)?[Pg. No. 119]
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25 In the previous chapter, a weightlifter is shown holding a barbell steady in her hands.
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26 Is it possible to build a perpetual motion machine, which once started, could continue doing useful work forever, without any fuel or electricity?
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27 When you pedal a bicycle on a flat road, your muscles supply energy.
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28 Two objects A and B of mass m and 4m have the same kinetic energy.
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29 Does the potential energy of an object near the surface of the Earth change if it moves with constant velocity in the horizontal direction?
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30 Does the kinetic energy of an object which moves with constant velocity change with its position?[Pg. No. 123]
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