MCQ 511 Mark
The radius of a wheel is 0.25m. The number of revolutions it will make to travel a distance of 11km will be:
- A2800
- B4000
- C5500
- ✓7000
Answer
View full question & answer→Correct option: D.
7000
We have given the radius of the wheel that is 0.25cm.
We know that distance covered by the wheel in one revolution$=\frac{\text{Distance moved}}{\text{Number of revolution}}$
Distance covered by the wheel in one revolution is equal to the circumference of the wheel.
$2\pi\text{r}=\frac{\text{Distance moved}}{\text{Number of revolutions}} \dots(1)$
Distance moved is given as 11km so we will first convert it to m.
$\therefore$ 11km = 11000m
Now we will substitute the values in equation (1),
$2\times\pi\times0.25=\frac{11000}{\text{Number of revolutions}}$
Now we will substitute $\pi=\frac{22}{7}$
$2\times\frac{22}{7}\times0.25=\frac{11000}{\text{Number of revolutions}}$
Simplifying equation (1) we get,
Number of revolutions $=\frac{11000\times7}{2\times22\times0.25}$
$\therefore$ Number of revolutions $=\frac{11000\times7}{22\times0.5}$
$\therefore$ Number of revolution $=\frac{1000\times7}{2\times0.5}$
$\therefore$ Number of revolution $=\frac{7000}{1}$
$\therefore$ Number of revolutions = 7000
Therefore, it will make 7000 revolutions to travel a distance of 11km.
Hence, the correct answer is option (d).
We know that distance covered by the wheel in one revolution$=\frac{\text{Distance moved}}{\text{Number of revolution}}$
Distance covered by the wheel in one revolution is equal to the circumference of the wheel.
$2\pi\text{r}=\frac{\text{Distance moved}}{\text{Number of revolutions}} \dots(1)$
Distance moved is given as 11km so we will first convert it to m.
$\therefore$ 11km = 11000m
Now we will substitute the values in equation (1),
$2\times\pi\times0.25=\frac{11000}{\text{Number of revolutions}}$
Now we will substitute $\pi=\frac{22}{7}$
$2\times\frac{22}{7}\times0.25=\frac{11000}{\text{Number of revolutions}}$
Simplifying equation (1) we get,
Number of revolutions $=\frac{11000\times7}{2\times22\times0.25}$
$\therefore$ Number of revolutions $=\frac{11000\times7}{22\times0.5}$
$\therefore$ Number of revolution $=\frac{1000\times7}{2\times0.5}$
$\therefore$ Number of revolution $=\frac{7000}{1}$
$\therefore$ Number of revolutions = 7000
Therefore, it will make 7000 revolutions to travel a distance of 11km.
Hence, the correct answer is option (d).





