One person drags a 10 kilogram
sandbag at a distance of 8 meters
employing a horizontal force of
90 N. Then lift the sandbag at a
height of 1.5 meters, calculate the
total work done by the person.
A boy leaves a 0.4 kilogram stone
from the top of a 25 meter−high
tower. Given g=10 m/s^2 , calvulate
the total work done by the force of the
weight until the stone hits the ground
a number consists of digits 1 and 2.
the sum of its digits is 2018.
if the number is multiplied with 5,
the sum of the digits will be 10000.
find how many digits this number
has.