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Usha Bhandari
Asked: 2022-11-10T09:34:29+05:30 In:

Is the work required to be done by an external force on an object on a frictionless , horizontal surface to accelerate it from a speed `v` to a speed `2y`
A. equal to the work required to accelerate the object from `t = 0` to `v`.
B. twice the work required to accelerate the object from `v = 0` to `v`.
C. three time the work required to accelerate the object from `v = 0` to `v`.
D. four time the work required to accelerate the object from ` 0` to `v`. Or

Is the work required to be done by an external force on an object on a frictionless , horizontal surface to accelerate it from a speed `v` to a speed `2y`
A. equal to the work required to accelerate the object from `t = 0` to `v`.
B. twice the work required to accelerate the object from `v = 0` to `v`.
C. three time the work required to accelerate the object from `v = 0` to `v`.
D. four time the work required to accelerate the object from ` 0` to `v`. Or
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  1. Correct Answer – C
    The net work needed to accelerate the object from `v= 0` to `v` is
    `W_(1) = KE_(1 f) – KE_(1 i) = (1)/(2) mv^(2) – (1)/(2) m (0) ^(2) = (1)/(2) mv^(2)`
    The work required to accelerate the object from speed `v` to speed `2 v` is
    `W_(2) = KE_(2 f) – KE_(2 i) = (1)/(2) m(2 v)^(2) – (1)/(2) mv^(2)`
    ` = (1)/(2) m (4 v^(2) – v^(2)) = 3 ((1)/(2) mv^(2)) = 3 W_(1)`

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