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4 years ago

13. If a track athlete runs an 800 m race at a constant speed of 2 m/s, how long will it

Physics

2 answers:

enyata [817]4 years ago

7 0

A.6.7
Explanation

800 / 2 = 400
400 / 60 = 6.67
6.67 = 6.7

german4 years ago

3 0

Answer:

A. 6.7 min

Explanation:

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What do you think causes the rising and sinking of molten rock in the mantle?

Svet_ta [14]

Answer:

Heyyy hope this helps

Convection currents describe the rising, spread, and sinking of gas, liquid, or molten material caused by the application of heat.

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3 years ago

What is the equation that defines work

mina [271]

Work=force*displacment

3 0

3 years ago

Because of your success in physics class you are selected for an internship at a prestigious bicycle company in its research and

tiny-mole [99]

To develop the problem it is necessary to apply the equations related to the moment of inertia.

The given values can be defined as,

$M = 1.0 kg$

$r = 0.5 m$

$m = 10 g$

$I = 0.280 kg.m^2$

According to the definition of the moment of inertia applied to the exercise we can arrive at the equation that,

$I = I_{rim} + n * I_{spoke}$

Where n is the number of spokes necessary to construct the wheel.

$I_{rim} = M*r^2 = 1.0 * 0.5^2$

$I_{spoke} = \frac{1}{3} * m * r^2 = \frac{1}{3}* 10 * 10^-3 * 0.5^2$

Replacing the values at the general equation we have,

$0.280 = 1.0 * 0.5^2 + n * (1/3 * 10 * 10^-3 * 0.5^2 )$

Solving for n,

$n = 36$

Therefore the number of spokes necessary to construct the wheel is 36

PART B) The mass of the wheel is given by the sum of all masses and the total spokes, then

$M_w= M + n*m$

$M_w = 1.0 + 36* 10 * 10^{-3} Kg$

$M_w = 1.36 Kg$

Therefore the mass of the wheel must be of 1.36Kg

4 0

4 years ago

Suppose Earth's gravitational force were decreased by half. How would this change affect a game of basketball? Write a paragraph

timama [110]

If the gravitational force were<span> decreased by half, there would be lack of gravity on earth. Hence, it would basically affect the velocity, speed, and the distance travelled in any direction by basketball players and the ball. The basketball would bounce higher and come down in a slower speed. Whereas for the players, they would be able to leap higher from the floor.</span><span> </span>

7 0

4 years ago

Very large forces are produced in joints when a person jumps from some height to the ground. Calculate the force produced if an

krok68 [10]

Answer:

A) 31 kJ

B) 1.92 KJ

C) 40 , 2.48

Explanation:

weight of person ( m ) = 79 kg

height of jump ( h ) = 0.510 m

Compression of joint material ( d ) = 1.30 cm ≈ 0.013 m

A) calculate the force

Fd = mgh

F = mgh / d

W = mg

F(net) = W + F = mg ( 1 + $\frac{h}{d} )$

= 79 * 9.81 ( 1 + (0.51 / 0.013) )

= 774.99 ( 40.231 ) ≈ 31 KJ

B) calculate the force when the stopping distance = 0.345 m

d = 0.345 m

Fd = mgh hence F = mgh / d

F(net) = W + F = mg ( 1 + $\frac{h}{d} )$

= 79 * 9.81 ( 1 + (0.51 / 0.345) )

= 774.99 ( 2.478 ) = 1.92 KJ

C) Ratio of force in part a with weight of person

= 31000 / ( 79 * 9.81 ) = 31000 / 774.99 = 40

Ratio of force in part b with weight of person

= 1920 / 774.99 = 2.48

4 0

3 years ago