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zlopas [31]
2 years ago
6

A sprinter speeds up to 3 m/s during the last 2 seconds of the race with an

Physics
1 answer:
quester [9]2 years ago
4 0

Answer:

<em>The initial speed of the sprinter was 2.2 m/s</em>

Explanation:

<u>Constant Acceleration Motion</u>

It's a type of motion in which the velocity of an object changes by an equal amount in every equal period of time.

The following relation applies:

v_f=v_o+at

Where a is the constant acceleration, vo the initial speed, vf the final speed, and t the time.

The sprinter speeds up from an unknown initial speed to vf=3 m/s in t=2 seconds with an acceleration of a=0.4~m/s^2.

To find the initial speed, we solve the equation for vo:

v_o=v_f-at

Substituting the values:

v_o=3-0.4*2

v_o=3-0.8

v_o=2.2~m/s

The initial speed of the sprinter was 2.2 m/s

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Maximum voltage produced in an AC generator completing 60 cycles in 30 sec is 250V. (a) What is period of armature? (b) How many
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Answer:

a. 2 Hz b. 0.5 cycles c . 0 V

Explanation:

a. What is period of armature?

Since it takes the armature 30 seconds to complete 60 cycles, and frequency f = number of cycles/ time = 60 cycles/ 30 s = 2 cycles/ s = 2 Hz

b. How many cycles are completed in T/2 sec?

The period, T = 1/f = 1/2 Hz = 0.5 s.

So, it takes 0.5 s to complete 1 cycles. At t = T/2 = 0.5/2 = 0.25 s,

Since it takes 0.5 s to complete 1 cycle, then the number of cycles it completes in 0.25 s is 0.25/0.5 = 0.5 cycles.

c. What is the maximum emf produced when the armature completes 180° rotation?

Since the emf E = E₀sinθ and when θ = 180°, sinθ = sin180° = 0

E = E₀ × 0 = 0

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8 0
2 years ago
What is the likely identity of a metal if a sample has a mass of 63.5 g when measured in air and an apparent mass of 60.2 g when
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Answer:

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Mass of water displaced = 3.3 g

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