Which of the following statements are true? E.g., if the first is true and the r

Question

Which of the following statements are true? E.g., if the first is true and the rest false, enter TFFFF. i. Two identical masses are placed on frictionless slopes at identical heights. The first slope makes an angle of 30 degree with respect to the horizontal, the second slope makes as angle of 40 degree, Both balls are released simultaneously, At the bottom of the slope, both balls have the same speed. ii. Negative net work done on an object always reduces the object's kinetic energy. iii. If a force acts downwards, it does negative work. iv. Two balls with different masses reach the same height when shot into the air form the ground. If there is no air drug, both balls must have left the ground with the same speed. v. Consider a train that pulls a wagon. By Newton's third law, the wagon pulls on the train with an equal opposite force, therefore the work done by the train must be zero.

Explanation / Answer

i) true because final kinetic energy depends on work by gravity which depends only on height

ii) false the potentil energy may also decrease

iii) false because force does negative wok when the dispalcement is opposite to the direction of force

iv) true because the height is independent of mass of the object . it is always sqrt(2gH)

v) false : when work is calculated the force is calcualted on the train not the wagon. the wagon is sparate and train is separate for work calucaltion

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