Ask question

Ask question

All categories

3 years ago

10

A hoodlum throws a stone vertically downward with an initial speed of 12.0 m/s from the roof of a building,30.0 m above the grou

nd. (a) how long does it take the stone to reach the ground

1 answer:

bogdanovich [222]3 years ago

8 0

S=ut +1/2at2
30=12t+1/2*10*t2
5t2+12t-30=0

You might be interested in

For a certain spring, k = 15N/m. A weight is hung from the spring, stretching it from 0.3m to 0.4m. What force did the weight pr

Mashcka [7]

The stretch of the spring is
$\Delta x = 0.4 m-0.3 m=0.1 m$
The constant of the spring is k=15 N/m, so we can find the force produced by the weight by using Hook's law:
$F=k\Delta x=(15 N/m)(0.1 m)=1.5 N$

8 0

3 years ago

In an undeveloped country, the rural areas will often be off the grid, with no access to consistent electricity. For a household

AveGali [126]

In an undeveloped country, the rural areas will often be off the grid, with no access to consistent electricity. For a household living in this situation, <u>wood</u> would most likely be used to heat the home in the winter.

<u>Explanation:</u>

With the help of wood, we can burn it and make fire to heat the house in winter. In the earlier days, wood was used to produce heat and was used for cooking and other purposes.

So when a rural area does not have electricity,stoves would be fired with either biomass fuels, such as wood, branches, twigs or dung, or coal. Also for heating the home, the same would be used. These fuels are collected from the local environment in rural areas and purchased through markets in urban areas. Even now in some countries like India and China use wood or any other biomass fuel for heating and cooking.

5 0

3 years ago

A ball is thrown toward a cliff of height h with a speed of 33 m/s and an angle of 60∘ above horizontal. It lands on the edge of

Veseljchak [2.6K]

Answer:

(a). The height of the cliff is 41.67 m.

(b). The maximum height of the ball is 41.67 m

(c). The ball's impact speed is 16.52 m/s.

Explanation:

Given that,

Speed = 33 m/s

Angle = 60°

Time = 3.0 sec

(a). We need to calculate the height of the cliff

Using equation of motion

$h=ut-\dfrac{1}{2}gt^2$

$h=(u\sin60)\times t-\dfrac{1}{2}gt^2$

Put the value into the formula

$h=33\times\sin60\times3.0-\dfrac{1}{2}\times9.8\times(3.0)^2$

$h=41.6\ m$

(b). We need to calculate the maximum height of the ball

Using formula of height

$h_{max}=\dfrac{(u\sin\theta)^2}{2g}$

Put the value into the formula

$h=\dfrac{(33\sin60)^2}{2\times 9.8}$

$h=41.67\ m$

(c). We need to calculate the vertical component of velocity of ball

Using equation of motion

$v=u-gt$

$v=u\sin\theta-gt$

Put the value into the formula

$v_{y}=33\times\sin 60-9.8\times3.0$

$v_{y}=-0.82\ m/s$

We need to calculate the horizontal component of velocity of ball

Using formula of velocity

$v_{x}=u\cos\theta$

Put the value into the formula

$v_{x}=33\times\cos60$

$v_{x}=16.5\ m/s$

We need to calculate the ball's impact speed

Using formula of velocity

$v=\sqrt{v_{x}^2+v_{y}^2}$

Put the value into the formula

$v=\sqrt{(16.5)^2+(-0.82)^2}$

$v=16.52\ m/s$

Hence, (a). The height of the cliff is 41.67 m.

(b). The maximum height of the ball is 41.67 m

(c). The ball's impact speed is 16.52 m/s.

3 0

3 years ago

Tony has a mass of 50 kg, and his friend Sam has a mass of 45 kg. Assume that both friends push off on their rollerblades with t

Citrus2011 [14]

Answer:

Sam

Explanation:

Hes lighter

3 0

3 years ago

What is the heat flux (W/m^2), due to radiation heat transfer, from a black body if the surface temperature is 1000C? The convec

12345 [234]

Answer:

55000 W/m²

Explanation:

Parameters given:

Surface temperature, T = 1000°C

Hear transfer coefficient, h = 55 W/m²C

Convection heat transfer coefficient is given as:

h = Heat flux/Temperature

Hence, Heat Flux, q, is given as:

q = h * T

q = 55 * 1000 = 55000 W/m²C

7 0

3 years ago

Read 2 more answers