A ball is thrown straight up in the air and just before it lands it is travelling -47.5 m/s. How long was the ball in the air?

A 2.0 kg wood block is launched up a wooden ramp that is inclined at a 30˚ angle. The block’s initial speed is 10 m/s. What vert

WARRIOR [948]

Answer:

The wood block reaches a height of 4.249 meters above its starting point.

Explanation:

The block represents a non-conservative system, since friction between wood block and the ramp is dissipating energy. The final height that block can reach is determined by Principle of Energy Conservation and Work-Energy Theorem. Let suppose that initial height has a value of zero and please notice that maximum height reached by the block is when its speed is zero.

$\frac{1}{2}\cdot m \cdot v^{2} = m \cdot g\cdot h + \mu_{k}\cdot m\cdot g\cdot s \cdot \sin \theta$

$\frac{1}{2}\cdot v^{2} = g\cdot h + \mu_{k}\cdot g\cdot \left(\frac{h}{\sin \theta} \right)\cdot \sin \theta$

$\frac{1}{2}\cdot v^{2} = g\cdot h +\mu_{k}\cdot g\cdot h$

$\frac{1}{2}\cdot v^{2} = (1 +\mu_{k})\cdot g\cdot h$

$h = \frac{v^{2}}{2\cdot (1 + \mu_{k})\cdot g}$ (1)

Where:

$h$ - Maximum height of the wood block, in meters.

$v$ - Initial speed of the block, in meters per second.

$\mu_{k}$ - Kinetic coefficient of friction, no unit.

$g$ - Gravitational acceleration, in meters per square second.

$m$ - Mass, in kilograms.

$s$ - Distance travelled by the wood block along the wooden ramp, in meters.

$\theta$ - Inclination of the wooden ramp, in sexagesimal degrees.

If we know that $v = 10\,\frac{m}{s}$ , $\mu_{k} = 0.20$ and $g = 9.807\,\frac{m}{s^{2}}$ , then the height reached by the block above its starting point is:

$h = \frac{\left(10\,\frac{m}{s} \right)^{2}}{2\cdot (1+0.20)\cdot \left(9.807\,\frac{m}{s^{2}} \right)}$

$h = 4.249\,m$

The wood block reaches a height of 4.249 meters above its starting point.

5 0

3 years ago

Calculate the Energy (E) in joules for that wavelength and record it in the table below. Remember that E = HF, where h the Planc

Viefleur [7K]

In that formula for Energy, 'F' is the frequency of the photon.
But <u>Frequency = (speed)/(wavelength)</u>, so we can write the
Energy formula as
   E = h c / (wavelength) .

So the energy, in joules, of a photon with that wavelength, is . . .

   E = (6.6 x 10⁻³⁴) x (3 x10⁸) / (that wavelength)

      = <em>(1.989 x 10⁻²⁵) / (that wavelength, in meters) .</em>

5 0

3 years ago

Average velocity is different than average speed because calculating average velocity involves ?

VashaNatasha [74]

direction ................................................................

6 0

3 years ago

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Determine the amount of work done by the applied force when a 87 N force is applied to move a 15 kg object a horizontal

elena-s [515]

Answer:

391.5 J