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a 4 kg object is slowly lowered by 1.5m.how much work is done against gravity

4 into 1.5 = 6 j
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answer is 6
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The answer is -58.5J
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Hi The Legend, first we have to find the force i.e weight of the 4 kg by multiplying with g = 9.8 m/s^2 - the acceleration due to gravity
So weight = 4 * 9.8 = 39.2 N
Displacement made in the direction of weight 1.5 m. 
Actually no need to do work against gravity. Because it goes to a level of lower potential
We can say that work is performed by gravity. 
Work done = Force * displacement = 39.2 * 1.5 = 39.2 * 3/2 = 19,6 * 3 = 58.8 J 
If suppose we take the same 4 kg mass upward through 1.5 m then we do work against gravtiy and the same amount 58.8 J will be performed
If  we take g = 10 m/s^2 then 60 J of work will be performed
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58.8 J if g = 9.8 and 60 J if g = 10
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It should be -58.8J because the question says work done against gravity
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Given:- m=4 kg (in SI Unit) Displacement (d)=1.5 m (in SI Unit) a=g i.e. 9.8 m/s² Find:- Work done AGAINST Gravity Solution:- F=ma = (4×9.8) N = 39.2 N W=F×d×cos∅ or simply F×d {for beginners} ∅=180° {For AGAINST gravity} Therefore, (39.2×1.5×-1) J => -58.8 J is the answer **Thank You for Reading**
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