3. A horse is tied with a 2m long rope at a pole. What distance will the horse run around
the pole with a rope tightly stretched, if it takes one and a half round? Also find the
displacement of the horse.
4. What does the odometer of an automobile measure? Which of the following is moving
faster? Justify your answer. (i) A scooter moving with a speed of 300m/s, (ii) A car
moving with a speed of 36 km per hour.
5. An object travels 16m in 4 sec and then another 16m in 2 sec. What is the average
speed of the object?
ā€‹

Answer :

Explanation:

Let's address each question step by step:

**3. Horse tied with a 2m long rope at a pole:**

a) **Distance around the pole:**

The horse takes one and a half rounds around the pole with the rope tightly stretched.

- The length of the rope is 2 meters.

- To calculate the distance around the pole for one round, we use the circumference formula of a circle:

\[

\text{Circumference} = 2 \pi \times \text{radius}

\]

Here, the radius \( r \) is the length of the rope, which is 2 meters. Therefore,

\[

\text{Circumference} = 2 \pi \times 2 = 4 \pi \text{ meters}

\]

- For one and a half rounds, the distance covered by the horse:

\[

\text{Distance} = 1.5 \times 4 \pi = 6 \pi \text{ meters}

\]

b) **Displacement of the horse:**

- Displacement is the straight-line distance from the starting point to the ending point.

Since the horse ends up where it started (after one and a half rounds), the displacement is equal to the radius of the circle formed by the rope, which is 2 meters.

**4. Odometer of an automobile:**

- An odometer measures the total distance traveled by the automobile.

**Comparison of speeds:**

- Convert the speed of the car from km/h to m/s:

\[

\text{Speed of car} = 36 \times \frac{1000}{3600} = 10 \text{ m/s}

\]

- Now, compare the speeds:

- Speed of scooter = 300 m/s

- Speed of car = 10 m/s

Clearly, the scooter is moving faster than the car because its speed is 300 m/s compared to the car's speed of 10 m/s.

**5. Average speed of the object:**

- The object travels 16 meters in 4 seconds and then another 16 meters in 2 seconds.

To find the average speed, use the formula:

\[

\text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}}

\]

- Total distance traveled = 16 meters + 16 meters = 32 meters

- Total time taken = 4 seconds + 2 seconds = 6 seconds

\[

\text{Average Speed} = \frac{32 \text{ meters}}{6 \text{ seconds}} = 5.33 \text{ m/s}

\]

Therefore, the average speed of the object is \( 5.33 \) meters per second.

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