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2 years ago

Josie ran at an average speed of 16 m/s. if her mass 10 kg, what was her kinetic energy as she crosses her finish line?

2 answers:

4 0

I have to be honest with you . . . It's not possible to determine the answer with only the information given in the question.

Kinetic energy = (1/2) (mass) (speed squared).

Josie's Kinetic energy as she crosses the finish line is

(1/2) (her mass) (her speed as she crosses the finish line)².

That's (5 kg) x (her speed as she crosses the finish line)² .

But read the question again.

WE DON'T know her speed as she crosses the finish line.

The question only tells us her average speed for the whole race.

We can be confident that her <u><em>Average</em></u> Kinetic Energy was

(5 kg) (16 m/s)² = 1,280 Joules.

But we can't tell what her kinetic energy was as she crossed the finish line, beause we don't know what her speed was at that instant.

Helen [10]2 years ago

3 0

Answer: 1280 J

$KE=\frac{1}{2}mv^{2} \\\\KE= \frac{1}{2} (10 kg)(16 m/s)^2\\=1280 J$

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A ball starts from rest and undergoes uniform acceleration of 2.50m/s^2. What is the velocity of the ball 4s later?

erica [24]

Explanation:

Given:

v₀ = 0 m/s

a = 2.50 m/s²

t = 4 s

Find: v

v = at + v₀

v = (2.50 m/s²) (4 s) + 0 m/s

v = 10 m/s

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3 years ago

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A bodybuilder deadlifts a 215 kg weight to a height of 0.90 m above the ground. If he deadlifts this weight 10 times in a span o

wariber [46]

A bodybuilder deadlifts 215 kg to a height of 0.90 m. If he deadlifts this weight 10 times in 45 s, the power exerted is 421 W (b.)

<h3>What is power?</h3>

In physics, power (P) is the work (W) done over a period of time.

Step 1. Calculate the work done by the bodybuilder each time.

The bodybuilder lifts a 215 kg (m) weight to a height of 0.90 m (h). Being the gravity (g) of 9.81 m/s², we can calculate the work done in each lift using the following expression.

W = m × g × h = 215 kg × 9.81 m/s² × 0.90 m = 1.9 × 10³ N

Step 2. Calculate the work done by the bodybuilder over 10 times.

W = 10 × 1.9 × 10³ N = 1.9 × 10⁴ N

Step 3. Calculate the power exerted by the bodybuilder.

The bodybuilder does a work of 1.9 × 10⁴ N in a 45-s span.

P = 1.9 × 10⁴ N/45 s = 421 W

A bodybuilder deadlifts 215 kg to a height of 0.90 m. If he deadlifts this weight 10 times in 45 s, the power exerted is 421 W (b.)

Learn more about power here: brainly.com/question/911620

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1 year ago

After being accelerated through a potential difference of 5.33 kv, a singly charged carbon ion (12c) moves in a circle of radius

LekaFEV [45]

I'm stuck on the same question, as well :(

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3 years ago

A cat leaps to catch a bird. if the cat's jump was at 60.0° off the ground and its initial velocity was 2.74 m/s, what is the hi

user100 [1]

Answer:

0.29 m

Explanation:

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3 years ago

Q11) If you were standing at the top of a building and you dropped a rock.

Dafna1 [17]

Answer:

Part A

The distance travel by the rock is approximately 132.496 m

Part B

The speed when the rock hits the ground is approximately 50.96 m/s

Explanation:

Part A

The question is focused on the kinetics equation of a free falling object

The given parameter is the time it takes the rock to hit the ground, t = 5.2 s

For an object in free fall, we have;

h = 1/2·g·t²

Where;

h = The height from which the object is dropped

g = The acceleration due to gravity ≈ 9.8 m/s²

t = The time taken to travel the distance, h = 5.2 s

∴ h = 1/2 × 9.8 m/s² × (5.2 s)² ≈ 132.496 m

The distance travel by the rock, h ≈ 132.496 m

Part B

The speed, 'v', when the rock hits the ground, is given by the following kinematic equation,

v = g·t

∴ v = 9.8 m/s² × 5.2 s = 50.96 m/s

The speed when the rock hits the ground, v ≈ 50.96 m/s.

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2 years ago