Aman takes 20 seconds to climb 5m up a ladder. he weighs 720n. calculate the power he must deliver to do this.

Power = 180 Watt.

Explanation:

W = Work done = m x g x H.

m = mass of the body.

g = acceleration due to gravity = 9.8 m/s^2.

W = weight of the body = m x g = 720 N.

H = height of the body = 5 m.

t = Time = 20 s.

Plugging the above values in the formula we get:

W = 720 x 5 = 3600 J.

Power =

           = = 180 Watt.

Therefore the required value of power = 180 Watt.

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

answer: the rock sample is a sedimentary rock.

explanation:

it is given that:

mass of rock sample, m = 2.7 g

volume of rock sample,

so, density of rock sample will be

since, the density of rock sample is . hence, the rock sample is a sedimentary rock, whose densities varies between .