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scoundrel [369]

2 years ago

7

a stone is dropped from rest at an initial height h above the surface of the earth. Show that the speed with which it strikes th

e ground is v

1 answer:

Ksju [112]2 years ago

5 0

Answer:

$v=\sqrt{2gh}$

Explanation:

We could use conversation of energy. Total distance the stone will cover will be

$h=\frac{1}{2} g t^{2}$

the Final velocity will be

$v=gt\\v=g\sqrt{\frac{2h}{g} }\\ v=\sqrt{2gh}$

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A cannonball is launched at ground level at an angle of 30° above the horizontal with

user100 [1]

Answer:

use the kinematics equations and solve for time, after that use dleta dx=Vi*delta time

8 0

3 years ago

Read 2 more answers

The combination of an applied force and a friction force produces a constant total torque of 35.5 N · m on a wheel rotating abou

Cerrena [4.2K]

Answer:

a) $I = 19.799\,kg\cdot m^{2}$ , b) $T = -3.405\,N\cdot m$ , c) $n_{T} \approx 54.842\,rev$

Explanation:

a) The net torque is:

$T = I\cdot \alpha$

Let assume a constant angular acceleration, which is:

$\alpha = \frac{\omega-\omega_{o}}{t}$

$\alpha = \frac{10.4\,\frac{rad}{s} - 0\,\frac{rad}{s} }{5.80\,s}$

$\alpha = 1.793\,\frac{rad}{s^{2}}$

The moment of inertia of the wheel is:

$I = \frac{T}{\alpha}$

$I = \frac{35.5\,N\cdot m}{1.793\,\frac{rad}{s^{2}} }$

$I = 19.799\,kg\cdot m^{2}$

b) The deceleration of the wheel is due to the friction force. The deceleration is:

$\alpha = \frac{\omega-\omega_{o}}{t}$

$\alpha = \frac{0\,\frac{rad}{s} - 10.4\,\frac{rad}{s}}{60.4\,s}$

$\alpha = - 0.172\,\frac{rad}{s^{2}}$

The magnitude of the torque due to friction:

$T = (19.799\,kg\cdot m^{2})\cdot (-0.172\,\frac{rad}{s^{2}} )$

$T = -3.405\,N\cdot m$

c) The total angular displacement is:

$\theta_{T} = \theta_{1} + \theta_{2}$

$\theta_{T} = \frac{(10.4\,\frac{rad}{s} )^{2}-(0\,\frac{rad}{s} )^{2}}{2\cdot (1.793\,\frac{rad}{s^{2}} )} + \frac{(0\,\frac{rad}{s} )^{2}-(10.4\,\frac{rad}{s} )^{2}}{2\cdot (-0.172\,\frac{rad}{s^{2}} )}$

$\theta_{T} = 344.580\,rad$

The total number of revolutions of the wheel is:

$n_{T} = \frac{\theta_{T}}{2\pi}$

$n_{T} = \frac{344.580\,rad}{2\pi}$

$n_{T} \approx 54.842\,rev$

5 0

3 years ago

A ball is dropped from a height of 23.5 meters. Assuming no air resistance, how many seconds will it take the ball to hit the

Alex Ar [27]

Answer:

About 2.19 seconds

Explanation:

$d=v_ot+\dfrac{1}{2}at^2$

Since the ball is dropped from rest, there is no initial velocity, and you can write the following equation:

$23.5=\dfrac{1}{2}(9.8)t^2 \\\\t^2\approx 4.79 \\\\t\approx 2.19s$

Hope this helps!

8 0

2 years ago

Read 2 more answers

A car on a roller coaster starts at zero speed at an elevation above the ground of 26 m. It coasts down a slope, and then climbs

nirvana33 [79]

The speed of the car at the top of the hill is 14m/s

<u>Explanation:</u>

given that

Initial velocity u of the car=0 m/s

The distance can be determined by finding out the difference between the elevation of the first slope and second slope.

elevation of the first slope=26 m

elevation of second slope=16m

distance s=26-16=10 m

acceleration due to gravity g=9.8 m/s2

speed of the car at the top of the hill can be determined by using the equation

$v^2=u^2+2as\\v^2=0^2+2\times 9.8\times 10\\=196\\v=\sqrt{196} =14m/s$

speed of the car at the top of the hill is 14m/s

5 0

2 years ago

Help please! this is science :)

SSSSS [86.1K]

Answer: Answer is B

Explanation: These are all explaining on how multipler different types of cells work together on how the body cooperates with other cells in order to maintain peace within the body however B using the process of elimination doesn't and says on the unicellular organisms work out the differnet parts in the body

7 0

2 years ago