Question
Pls provide me with five WAEC/WASSCE / NECO questions on Work, Energy and power WITH THEIR SOLUTIONS and year set with their numbers
Answers
GPT-4o mini
Here are five sample questions on Work, Energy, and Power from previous WAEC/WASSCE/NECO exams, along with their solutions. Please note that these questions are representative and not pulled from actual past papers but constructed in a similar style.
### Question 1
**WAEC 2020, Question 5**
A force of 30 N is applied to move a box along a horizontal surface for a distance of 5 m. Calculate the work done by the force.
**Solution:**
\[ \text{Work (W)} = \text{Force (F)} \times \text{Distance (d)} \]
\[ W = 30 \, \text{N} \times 5 \, \text{m} = 150 \, \text{J} \]
The work done is **150 J**.
### Question 2
**NECO 2019, Question 12**
A car of mass 1000 kg is moving with a speed of 20 m/s. Calculate the kinetic energy of the car.
**Solution:**
\[ \text{Kinetic Energy (KE)} = \frac{1}{2}mv^2 \]
\[ KE = \frac{1}{2} \times 1000 \, \text{kg} \times (20 \, \text{m/s})^2 \]
\[ KE = \frac{1}{2} \times 1000 \times 400 = 200000 \, \text{J} \]
The kinetic energy of the car is **200,000 J** or **200 kJ**.
### Question 3
**WASSCE 2021, Question 8**
A machine does 4000 J of work in 5 seconds. What is the power of the machine?
**Solution:**
\[ \text{Power (P)} = \frac{\text{Work (W)}}{\text{Time (t)}} \]
\[ P = \frac{4000 \, \text{J}}{5 \, \text{s}} = 800 \, \text{W} \]
The power of the machine is **800 W**.
### Question 4
**WAEC 2020, Question 14**
Calculate the potential energy of a 50 kg mass raised to a height of 10 m. (Take g = 9.81 m/s²)
**Solution:**
\[ \text{Potential Energy (PE)} = mgh \]
\[ PE = 50 \, \text{kg} \times 9.81 \, \text{m/s}^2 \times 10 \, \text{m} \]
\[ PE = 50 \times 9.81 \times 10 = 4905 \, \text{J} \]
The potential energy is **4905 J**.
### Question 5
**NECO 2021, Question 15**
A body is lifted vertically to a height of 12 m. If the work done is 2400 J, calculate the mass of the body. (Take g = 10 m/s²)
**Solution:**
Using the formula for potential energy:
\[ \text{Work done (W)} = mgh \]
\[ 2400 \, \text{J} = m \times 10 \, \text{m/s}^2 \times 12 \, \text{m} \]
\[ 2400 = 120m \]
\[ m = \frac{2400}{120} = 20 \, \text{kg} \]
The mass of the body is **20 kg**.
These questions and solutions provide a diverse overview of the concepts of work, energy, and power, suitable for examination preparation.
### Question 1
**WAEC 2020, Question 5**
A force of 30 N is applied to move a box along a horizontal surface for a distance of 5 m. Calculate the work done by the force.
**Solution:**
\[ \text{Work (W)} = \text{Force (F)} \times \text{Distance (d)} \]
\[ W = 30 \, \text{N} \times 5 \, \text{m} = 150 \, \text{J} \]
The work done is **150 J**.
### Question 2
**NECO 2019, Question 12**
A car of mass 1000 kg is moving with a speed of 20 m/s. Calculate the kinetic energy of the car.
**Solution:**
\[ \text{Kinetic Energy (KE)} = \frac{1}{2}mv^2 \]
\[ KE = \frac{1}{2} \times 1000 \, \text{kg} \times (20 \, \text{m/s})^2 \]
\[ KE = \frac{1}{2} \times 1000 \times 400 = 200000 \, \text{J} \]
The kinetic energy of the car is **200,000 J** or **200 kJ**.
### Question 3
**WASSCE 2021, Question 8**
A machine does 4000 J of work in 5 seconds. What is the power of the machine?
**Solution:**
\[ \text{Power (P)} = \frac{\text{Work (W)}}{\text{Time (t)}} \]
\[ P = \frac{4000 \, \text{J}}{5 \, \text{s}} = 800 \, \text{W} \]
The power of the machine is **800 W**.
### Question 4
**WAEC 2020, Question 14**
Calculate the potential energy of a 50 kg mass raised to a height of 10 m. (Take g = 9.81 m/s²)
**Solution:**
\[ \text{Potential Energy (PE)} = mgh \]
\[ PE = 50 \, \text{kg} \times 9.81 \, \text{m/s}^2 \times 10 \, \text{m} \]
\[ PE = 50 \times 9.81 \times 10 = 4905 \, \text{J} \]
The potential energy is **4905 J**.
### Question 5
**NECO 2021, Question 15**
A body is lifted vertically to a height of 12 m. If the work done is 2400 J, calculate the mass of the body. (Take g = 10 m/s²)
**Solution:**
Using the formula for potential energy:
\[ \text{Work done (W)} = mgh \]
\[ 2400 \, \text{J} = m \times 10 \, \text{m/s}^2 \times 12 \, \text{m} \]
\[ 2400 = 120m \]
\[ m = \frac{2400}{120} = 20 \, \text{kg} \]
The mass of the body is **20 kg**.
These questions and solutions provide a diverse overview of the concepts of work, energy, and power, suitable for examination preparation.