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3 years ago

Which body exerts the force that propels the sprinter, the blocks or the sprinter?

1 answer:

5 0

Answer: The blocks

Explanation:
When the sprinter takes off, he/she presses hard on the block.
The blocks apply an equal and opposite force to the sprinter according to Newton's 3rd law of motion.
The reaction force from the blocks gives the sprinter the initial acceleration to begin the race.

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Where c is a constant that depends on the initial gas pressure behind the projectile. The initial position of the projectile is

Ronch [10]

Complete Question

A gas gun uses high pressure gas tp accelerate projectile through the gun barrel.

If the acceleration of the projective is : a = c/s m/s2

Where c is a constant that depends on the initial gas pressure behind the projectile. The initial position of the projectile is s= 1.5m and the projectile is initially at rest. The projectile accelerates until it reaches the end of the barrel at s=3m. What is the value of the constant c such that the projectile leaves the barrel with velocity of 200m/s?

Answer:

The value of the constant is $c = 28853.78 \ m^2 /s^2$

Explanation:

From the question we are told that

The acceleration is $a = \frac{c}{s}\ m/s^2$

The initial position of the projectile is s= 1.5m

The final position of the projectile is $s_f = 3 \ m$

The velocity is $v = 200 \ m/s$

Generally $time = \frac{ds}{dv}$

and acceleration is $a = \frac{v}{time }$

$a = v \frac{dv}{ds}$

=> $vdv = a ds$

$vdv = \frac{c}{s} ds$

integrating both sides

$\int\limits^a_b vdv = \int\limits^c_d \frac{c}{s} ds$

Now for the limit

a = 200 m/s

b = 0 m/s

c = s= 3 m

d = $s_f$ = 1.5 m

So we have

$\int\limits^{200}_{0} vdv = \int\limits^{3}_{1.5} \frac{c}{s} ds$

$[\frac{v^2}{2} ] \left | 200} \atop {0}} \right. = c [ln s]\left | 3} \atop {1.5}} \right.$

$\frac{200^2}{2} = c ln[\frac{3}{1.5} ]$

=> $c = \frac{20000}{0.69315}$

$c = 28853.78 \ m^2 /s^2$

5 0

3 years ago

Which of the following statements are true?

ale4655 [162]

Answer:

A) True. Voltmeters measure voltages

C) True. They are placed in parallel

E) True ammeters are used to measure current

Explanation:

The devices for voltage measurement are the voltmeter and ammeter

Voltmeters have very high intense resistance and are placed in parallel

The ammeters have very small resist and are placed in series

Based on this establishment, let's analyze the statements

A) True. Voltmeters measure voltages

B) False has high intense resistance

C) True. They are placed in parallel

D) False ammeters are placed in series

E) True ammeters are used to measure current

F) False ammeters have a low internal resistance

4 0

3 years ago

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An object is thrown upward from the edge of a tall building as with a velocity of 10m/s. where will the object be 3s after it is

KonstantinChe [14]

20 m is the answer, hope that helps

6 0

3 years ago

When bitten by an animal, one should:

Scrat [10]

Answer:

consider rabies injections if the animal is not found

hope it helps

4 0

2 years ago

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How long can a person dribble a ball when being closely guarded by a

Katena32 [7]

Answer:

four seconds

Explanation:

A player who catches the ball and is being closely guarded may hold the ball for four seconds, then dribble the ball for four seconds, then hold the ball for another four seconds, then pass, will not be in violation of this rule.

7 0

3 years ago