Question

5.) the builders of the pyramids used a long ramp to lift 20,000 kg (22 ton) blocks. if a block rose 1 m in height while traveling 20 m along the ramps surface, how much uphill force was needed to push it up the ramp at constant velocity?
6.) how much work was done in raising one of the previous blocks to a height of 50 m?

Explanation:

Step1: Define given values (Q5)

Mass $m=20000\ \text{kg}$, height $h=1\ \text{m}$, ramp length $L=20\ \text{m}$, $g=9.8\ \text{m/s}^2$

Step2: Relate work done (Q5)

Work to lift = work against ramp force: $mgh = F \cdot L$

Step3: Solve for uphill force (Q5)

$F = \frac{mgh}{L} = \frac{20000 \times 9.8 \times 1}{20}$

Step4: Define values for work (Q6)

Height $H=50\ \text{m}$, $m=20000\ \text{kg}$

Step5: Calculate gravitational work (Q6)

Work $W = mgH = 20000 \times 9.8 \times 50$

Answer:

5.) $9800\ \text{N}$
6.) $9.8 \times 10^6\ \text{J}$