Question

The builders of the pyramids used a long ramp to lift 20000-kg (20.0-ton) blocks. If a block rose 0.800 m in height while traveling 20.0 m along the ramp’s surface, how much uphill force was needed to push it up the ramp at constant velocity? Use g=9.81 m/s2.

Answer 1

7848 N

Step-by-step explanation:

Recall: K.E = P.E = Fd

K.E =
`(1)/(2) mv^(2)`

P.E = mgh

Given parameters;

mass (m) = 20000 kg

height (h) = 0.8 m

distance (d) = 20 m

g is given as 9.81
`ms^(-2)`

Force (F) = ?

Comparing the above parameters with the equations to find F,

We will use P.E = Fd

i.e. mgh = Fd

making F the subject of the formula

F =
`(mgh)/(d)`

substitute for m, g, h and d

F =
`(20000 X 9.81 X 0.8)/(20) = 7848N`

Answer 2

force need to push it up is 7848 N

Step-by-step explanation:

given data

mass m = 20000 kg

height h = 0.800 m

length L = 20 m

to find out

how much uphill force

solution

we use here work done = potential energy

because here work is gravitational potential

so

work done = F × L

so

F × L = mgh

and

F = mgh / L

put here value

F = 20000(9.81) 0.800 / 20

F = 7848

so force need to push it up is 7848 N