Question

• ALWAYS use significant figure rules. Remember that these rules apply to all numbers that are measurements.

Answer 1

Total mechanical energy: D) 2800 J

Explanation:

The total mechanical energy of an object is given by

$E=KE+PE$

where:

$KE=\frac{1}{2}mv^2$ is the kinetic energy of the object, which is the energy possessed by the object due to its motion, where

m = mass of the object

v = speed

And

$PE=mgh$ is the gravitational potential energy of the object, the energy possessed by the object due to its location, where

$g=9.8 m/s^2$ is the acceleration due to gravity

h is the height of the object above the ground

For the body in this problem, we have:

m = 4.0 kg

v = 20 m/s

h = 50 m

Substituting, we find its total energy:

$E=\frac{1}{2}mv^2+mgh=\frac{1}{2}(4.0)(20)^2+(4.0)(9.8)(50)=2760 J \sim 2800 J$

Learn more about kinetic and potential energy:

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