A man lifts a load of 20 kg Frome The ground And put it on his head 1.4m above the ground . Calculate the work done by the man. :pweez: xD

Given parameters:

Mass of load = 20kg

Height of man = 1.4m

Unknown:

Work done by man = ?

Work done is the force applied to move a body in a particular direction.

Often times, it is mathematically expressed as;

           Work done  = Force x distance

In this problem, we use the formula of potential energy to find the work done;

     Work done  = Potential energy  = mgh

where m is the mass of the load

            g is the acceleration due to gravity  = 9.8m/s²

            h is the height of the body

Now, input the parameters, and solve for work done;

        Work done = 20 x 9.8 x 1.4  = 274.4J

The work done by man is  274.4J

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s