A mason worker throws the bricks to a height of $10 m$, at which the bricks reach with a velocity of $6 ms^{-1}$. The percentage of energy he is nearly ($g = 10 ms^{-2}$)
a) $15 \%$
b) $18 \%$
c) $220 \%$
d) $36 \%$
Answer
581.4k+ views
Hint : When an object is in action, it holds energy that is named kinetic energy. The potential energy held by the object is the power present in it by its position, which means potential energy is deposited energy in the object when work is performed on the object, but there is no difference in the velocity or the object's speed.
Complete step-by-step solution:
Height to which bricks throws, $h = 10 m$
Velocity of brick, $v = 6 ms^{-1}$
Potential Energy, $PE = mgh$
$\implies PE = m \times 10 \times 10 = 100m$
Kinetic Energy, $KE = \dfrac{1}{2} m v^{2}$
$\implies KE = \dfrac{1}{2} m 6^{2} = 18m$
Total work done by the man is equal to the sum of kinetic energy and potential energy.
$W = KE +PE$
$\implies W = 18m + 100m$
$\implies W = 118m$
Brick reaches with the velocity of $6 m s^{-1}$, there is wastage of energy due to kinetic energy.
Percentage of energy will be $\dfrac{KE}{W} \times 100$.
$\implies \dfrac{18m}{118m} \times 100 = 15.25 \%$.
The percentage of energy is nearly about $15 \%$.
Option (a) is correct.
Note: Work and energy are nearly related to each other. Work can be described as the transference of energy. For two objects, the work performed is represented as transferring energy from the primary object to the next object. Also, energy is determined as the ability to do work. Work is supposed to be done by a force when an object undergoing displacement parallels the force's line of action.
Complete step-by-step solution:
Height to which bricks throws, $h = 10 m$
Velocity of brick, $v = 6 ms^{-1}$
Potential Energy, $PE = mgh$
$\implies PE = m \times 10 \times 10 = 100m$
Kinetic Energy, $KE = \dfrac{1}{2} m v^{2}$
$\implies KE = \dfrac{1}{2} m 6^{2} = 18m$
Total work done by the man is equal to the sum of kinetic energy and potential energy.
$W = KE +PE$
$\implies W = 18m + 100m$
$\implies W = 118m$
Brick reaches with the velocity of $6 m s^{-1}$, there is wastage of energy due to kinetic energy.
Percentage of energy will be $\dfrac{KE}{W} \times 100$.
$\implies \dfrac{18m}{118m} \times 100 = 15.25 \%$.
The percentage of energy is nearly about $15 \%$.
Option (a) is correct.
Note: Work and energy are nearly related to each other. Work can be described as the transference of energy. For two objects, the work performed is represented as transferring energy from the primary object to the next object. Also, energy is determined as the ability to do work. Work is supposed to be done by a force when an object undergoing displacement parallels the force's line of action.
Recently Updated Pages
If x a + bt + ct2 where x is in meters and t is in class 11 physics CBSE

A car covers the first half distance between two places class 11 physics CBSE

The resultant of two vectors overrightarrow P and overrightarrow class 11 physics CBSE

Find the value of cos 135 class 11 maths CBSE

A mass M is held in place by an applied force F and class 11 physics CBSE

A solution of glucose in water is labelled as 10 dfracwv class 11 chemistry CBSE

Trending doubts
One Metric ton is equal to kg A 10000 B 1000 C 100 class 11 physics CBSE

Find the value of the expression given below sin 30circ class 11 maths CBSE

What do you mean by retardation What is its SI uni class 11 physics CBSE

Draw a diagram of nephron and explain its structur class 11 biology CBSE

10 examples of friction in our daily life

Difference between physical and chemical change class 11 chemistry CBSE

