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riadik2000 [5.3K]
3 years ago
11

A man has power of 90W and mass 60kg runs up a staircase in 40 second. If each step of staircase is 20m high calculate the numbe

r of steps
Physics
1 answer:
Zielflug [23.3K]3 years ago
5 0
Power is calculated by dividing the work done with the time interval of the motion. Work, on the other hand, is force times the distance traveled. Therefore, we can calculate as follows:<span>

Power=W/t = mgd/t
90 = 60(9.81)d / 40
d = 6.12 m

Number of steps = 20/6.12 = 3.27 or 3 steps</span>
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In one of the original Doppler experiments, a tuba was played at a frequency of 64.0 Hz on a moving flat train car, and a second
wolverine [178]

Answer:

 f_{beat} = 1.64\ Hz

Explanation:

given,

frequency of tuba.f = 64 Hz

Speed of train approaching, v = 8.50 m/s

beat frequency = ?

using Doppler's effect formula

 f' = f(\dfrac{v}{v-v_s})

v_s is the velocity of the source

v is the speed of sound, v = 340 m/s

now,

 f' = 64\times (\dfrac{340}{340 - 8.50})

       f' = 65.64 Hz

now, beat frequency is equal to

 f_{beat} = f' - f

 f_{beat} = 65.64 - 64

 f_{beat} = 1.64\ Hz

hence, beat frequency is equal to 1.64 Hz

3 0
3 years ago
Give 1 real life example of a scenario that takes advantage of the inverse relationship between force and time when impulse is c
OverLord2011 [107]

Answer:

On real life example of a scenario that takes advantage of the inverse relationship between force and time when impulse is constant is when making a serve with a lawn tennis racket

How It is an example of impulse is that when a serve is made by moving the bat slowly, the lawn tennis player uses less force and the ball is in contact with the string for longer a period

When however, the lawn tennis player moves the racket faster, with the strings of the racket highly tensioned  he uses more force and the ball also spends less time on the racket to produce the same momentum

Explanation:

The impulse of a force, ΔP is given by the following formula;

ΔP = F × Δt

Where ΔP is constant, we have;

F ∝ 1/Δt

Therefore, for the same impulse, when the force is increased, the time of contact is decreases and vice versa.

7 0
3 years ago
A hockey puck slides on the ice and eventually stops. How would Newton interpret this behavior?
azamat

That would be a the first law of newton's laws of motion because it stops from an external force

6 0
3 years ago
A yellow train of mass 100 kg is moving at 8 m/s towards an orange train of mass 200 kg traveling on the opposite direction on t
vladimir1956 [14]
Mass of yellow train, my = 100 kg

Initial Velocity of yellow train, = 8 m/s

mass of orange train = 200 kg

Initial Velocity of orange train = -1 m/s (since it moves opposite direction to the yellow train, we will put negative to show the opposite direction)

To calculate the initial momentum of both trains, we will use the principle of conservation of momentum which

The sum of initial momentum = the sum of final momentum


Since the question only wants the sum of initial momentum,

(100)(8) + (200)(-1) = 600 m/s

8 0
2 years ago
In a drill during basketball practice, a player runs the length of the 30-meter court and back. The player does this three times
Sergeeva-Olga [200]

Answer:

0 m/s

Explanation:

Average velocity of an object is given by the net displacement divided by time taken. Displacement is equal to the shortest path covered by the object.

In this problem, a player runs the length of the 30-meter court and back. The player does this three times in 60 seconds.

As the player runs the court and returns to the original point. It would mean that the shortest path covered is 0.

Average velocity = displacement/time

v=0/30

v = 0 m/s

Hence, the correct option is (1).

6 0
3 years ago
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