Advertisements
Advertisements
प्रश्न
The distance between Bholu’s and Golu’s house is 9 km. Bholu has to attend Golu’s birthday party at 7 o’clock. He started from his home at 6 o’clock on his bicycle and covered a distance of 6 km in 40 minutes. At that point, he met Chintu and spoke to him for 5 minutes and reached Golu’s birthday party at 7 o’clock. With what speed did he cover the second part of the journey? Calculate his average speed for the entire journey.
उत्तर
Distance between Bholu’s and Golu’s house = 9 km
Distance covered by Bholu in the first part of the journey
= 6 km
Time is taken to cover 6 km = 40 min
Distance covered by Bholu in the second part of the journey
= 9 − 6
= 3 km
Time is taken to cover 3 km
= 60 – (40 + 5)
=15 min
Speed of Bholu while covering the second part of the journey = `(3"km")/((15/60)"h")`
= 12 km/h
The average speed of Bholu for the entire journey
= `("Total distance")/("Time taken")`
= `(9"km")/(60 "min")`
= 9 km/h
APPEARS IN
संबंधित प्रश्न
A driver of a car travelling at 52 km h−1 applies the brakes and accelerates uniformly in the opposite direction. The car stops in 5 s. Another driver going at 3 km h−1 in another car applies his brakes slowly and stops in 10 s. On the same graph paper, plot the speed versus time graphs for the two cars. Which of the two cars travelled farther after the brakes were applied?
Given figure shows the distance-time graph of three objects A, B and C. Study the graph and answer the following questions:
- Which of the three is travelling the fastest?
- Are all three ever at the same point on the road?
- How far has C travelled when B passes A?
- How far has B travelled by the time it passes C?
Figure shows the distance-time graph for the motion of two vehicles A and B. Which one of them is moving faster?
Figure: Distance-time graph for the motion of two cars
A car is travelling at 20 m/s along a road. A child runs out into the road 50 m ahead and the car driver steps on the brake pedal. What must the car’s deceleration be if the car is to stop just before it reaches the child ?
Figure (a) shows the displacement-time graph for the motion of a body. Use it to calculate the velocity of the body at t = 1 s, 2 s and 3 s, and then draw the velocity-time graph in Figure (b) for it.
 |
 |
| (a) | (b) |
A spaceship is moving in space with a velocity of 60 kms−1. It fires its retro engines for 20 seconds and velocity is reduced to 55 kms−1. Calculate the distance travelled by a spaceship in 40 s, from the time of firing of the retro- rockets.
Write down the type of motion of a body in each of the following distance time-graph.
What are the uses of the graphical study of motion?
The slope of the distance-time curve is steeper/greater is the ______.
Assertion: The position-time graph of a uniform motion in one dimension of a body can have a negative slope
Reason: When the speed of the body decreases with time then, the position-time graph of the moving body has a negative slope.
