select the correct answer. a box with a mass of 7 kilograms is pushed up a ramp to a height of 5 meters…

select the correct answer. a box with a mass of 7 kilograms is pushed up a ramp to a height of 5 meters. what is the work done against the force of gravity? assume the ramp has negligible friction. a. 3.4×10² joules b. 6.9×10² joules c. 8.6×10² joules d. 1.7×10² joules

select the correct answer. a box with a mass of 7 kilograms is pushed up a ramp to a height of 5 meters. what is the work done against the force of gravity? assume the ramp has negligible friction. a. 3.4×10² joules b. 6.9×10² joules c. 8.6×10² joules d. 1.7×10² joules

Answer

Explanation:

Step1: Recall work - gravity formula

The work done against gravity $W = mgh$, where $m$ is mass, $g$ is acceleration due to gravity ($g = 9.8\ m/s^{2}$), and $h$ is height.

Step2: Substitute values

Given $m = 7\ kg$, $g=9.8\ m/s^{2}$, and $h = 5\ m$. Then $W=7\times9.8\times5$. $W = 7\times49=343\ J$. In scientific - notation, $W = 3.43\times 10^{2}\ J\approx3.4\times 10^{2}\ J$.

Answer:

A. $3.4\times 10^{2}$ joules