how much work is done lifting a 75 kg child 1.75m?
Work=change in potential energy
therefore W=mgh = 75kg*9.8m/s^2*1.75m
= 1286.25 J
75 * 9.81 * 1.75 Joules
To calculate the work done in lifting an object, you need to multiply the weight of the object by the height it is lifted. The weight of an object can be calculated using the formula weight = mass * acceleration due to gravity.
In this case, the mass of the child is given as 75 kg. The acceleration due to gravity is approximately 9.8 m/s^2. Therefore, the weight of the child can be calculated as:
Weight = mass * acceleration due to gravity = 75 kg * 9.8 m/s^2
Next, you need to multiply the weight of the child by the height it is lifted. The height in this case is given as 1.75 m. Therefore, the work done can be calculated as:
Work = weight * height = (75 kg * 9.8 m/s^2) * 1.75 m
Now we can perform the calculations:
Work = (75 kg * 9.8 m/s^2) * 1.75 m
= 735 kg·m^2/s^2 * 1.75 m
= 1286.25 Joules
Therefore, the work done in lifting a 75 kg child to a height of 1.75 m is 1286.25 Joules.