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3 years ago

A girl runs south 10 meters then turns around and walks back 3 meters

Physics

1 answer:

Svetlanka [38]3 years ago

6 0

Answer:

Explanation:

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A 60 cm diameter wheel accelerates from rest at a rate of 7 rad/s2. After the wheel has undergone 14 rotations, what is the radi

Mamont248 [21]

Answer:

$a=368.97\ m/s^2$

Explanation:

Given that,

Initial angular velocity, $\omega=0$

Acceleration of the wheel, $\alpha =7\ rad/s^2$

Rotation, $\theta=14\ rotation=14\times 2\pi =87.96\ rad$

Let t is the time. Using second equation of kinematics can be calculated using time.

$\theta=\omega_it+\dfrac{1}{2}\alpha t^2\\\\t=\sqrt{\dfrac{2\theta}{\alpha }} \\\\t=\sqrt{\dfrac{2\times 87.96}{7}} \\\\t=5.01\ s$

Let $\omega_f$ is the final angular velocity and a is the radial component of acceleration.

$\omega_f=\omega_i+\alpha t\\\\\omega_f=0+7\times 5.01\\\\\omega_f=35.07\ rad/s$

Radial component of acceleration,

$a=\omega_f^2r\\\\a=(35.07)^2\times 0.3\\\\a=368.97\ m/s^2$

So, the required acceleration on the edge of the wheel is $368.97\ m/s^2$ .

6 0

3 years ago

An electric pump rated 1.5 KW lifts 200kg of water through a vertical height of 6m in 10 secs: way is the efficiency of the pump

ruslelena [56]

Answer:

80%

Explanation:

Efficiency = Power output / Power input × 100 %

To calculate efficiency we need to find power output of electric pump.

We can use,

Work done = Energy change

Work done per second = Energy change per second

Work done per second = Power

Therefore, Power = Energy change per second

= Change in potential energy of water per second

=mgh / t

= 200× 10×6 / 10

= 1200 W = 1.2 kW

Now use the first equation to find efficiency,

Efficiency = $\frac{1.2}{1.5}$ × 100%

= 80 %

8 0

3 years ago

The Pangaea theory supports the theory of plate tectonics because _____.

shutvik [7]

It is based on the idea that all the present continents were on supercontinent.

8 0

3 years ago

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A player kicks a ball across the grass. what causes the ball to slow down to stop

vlada-n [284]

Answer: Friction

Explanation: Friction caused m by the ball rubbing against the grass and ground cause it to lose energy in the form of thermal energy and slow down

7 0

3 years ago

How do i figure out this question?

nikklg [1K]

Answer:

0.75 g/cm^3

Explanation:

The formula for density:

$\rho = \frac{m}{V}$

Where m is the mass and V is the volume.

So, we can substitute values for m and V:

$\rho = \frac{277}{370}\approx0.75$

Therefore, the density is 0.75 g/cm^3 (watch the units!)

8 0

3 years ago

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