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3 years ago

A train travels 55 kilometers in 2 hours, and then 52 kilometers in 5 hours. What is its average speed?

Physics

2 answers:

Dafna11 [192]3 years ago

6 0

Average speed = (total distance covered) / (time to cover the distance) .

Total distance covered = (55 km + 52 km) = 107 km

Time to cover the distance = (2 hrs + 5 hrs) = 7 hrs

Average speed = (107 km) / (7 hrs)

Average speed = 15.29 km/hour

bulgar [2K]3 years ago

4 0

The formula for working out speed is distance ÷ time.

55 km ÷ 2 hours = 27.5 km/h (average speed for first part of journey)

52km ÷ 5 hours = 10.4 km/h (average speed for second part of journey)

(27.5 + 10.4) ÷ 2 = 18.95 km/h (average speed throughout the journey)

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3 years ago

A spinning wheel on a fireworks display is initially rotating in a counterclockwise direction. The wheel has an angular accelera

nalin [4]

Answer:

5.74s

Explanation:

We can first solve for the initial angular velocity using the following formula

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3 years ago

A 0.03 kg golf ball is hit off the tee at a speed of 34 m/s. The golf club was in contact with the ball for 0.003 s. What is the

Liula [17]

Answer:

The average force on ball by the golf club is 340 N.

Explanation:

Given that,

Mass of the golf ball, m = 0.03 kg

Initial speed of the ball, u = 0

Final speed of the ball, v = 34 m/s

Time of contact, $\Delta t=0.003\ s$

We need to find the average force on ball by the golf club. We know that the rate of change of momentum is equal to the net external force applied such that :

$F=\dfrac{\Delta p}{\Delta t}\\\\F=\dfrac{mv-mu}{\Delta t}\\\\F=\dfrac{mv}{\Delta t}\\\\F=\dfrac{0.03\ kg\times 34\ m/s}{0.003\ s}\\\\F=340\ N$