What are the cues for a forehand stroke

2.5kg of water (C = 4189 J/(Kg x K)) is heated from T1 = 13.5 C to T2 = 22.5 C

kondor19780726 [428]

Answer:

338 K

Explanation:

$m_{1}$ = 2.5 kg, c = 4189 J/(kg K), $T_{1}$ = 13.5 $^{o} C$ , $T_{2}$ = 22.5 $^{o} C$

$m_{2}$ = 0.5 kg, $T_{3}$ = 20 $^{o} C$

Heat loss by hotter water = heat gained by cooler water

$m_{1}$ cΔT = $m_{2}$ cΔT

$m_{1}$ c( $T_{2}$ - $T_{1}$ ) = $m_{2}$ c( $T_{4}$ - $T_{3}$ )

2.5 x 4189 x (22.5 - 13.5) = 0.5 x 4189 x ( $T_{4}$ - 20)

2.5 x 4189 x 9 = 2094.5 ( $T_{4}$ - 20)

94252.5 = 2094.5 $T_{4}$ - 41890

94252.5 + 41890 = 2094.5 $T_{4}$

136142.5 = 2094.5 $T_{4}$

$T_{4}$ = $\frac{136142.5}{2094.5}$

= 65

$T_{4}$ = 65 $^{o} C$

But,

θ K = 273 + θ $^{o} C$

= 273 + 65

= 338

The final temperature of the water is 338 K.

3 0

3 years ago

You throw a stone upward from the top of a building at an angle of 25Â° to the horizontal and with an initial speed of 15 m/s. I

Alex787 [66]

Answer:

11.025 m

87.75 m

Explanation:

Time of flight(T) of a projectile = 2U(sin∅)/g

Where U = initial Velocity, g = acceleration due to gravity, ∅= angle of projection.

Make ∅ the subject of the the equation,

∅ = sin⁻¹[(T× g)/2U]

Where U = 15m/s, T= 3.0 s, g = 9.8 m/s²

∅ = sin⁻¹[(3 × 9.8)/(2×15)]

∅ = sin⁻¹(29.4/30)

∅= sin⁻¹(0.98) = 78.52°

Using the formula for maximum height of a projectile

H = U²sin²∅/2g

H = 15²(sin²78.52)/2 × 9.8

H = 225(0.98 × 0.98)/19.6

H = 216.09/19.6

H = 11.025 m

Range (R) = U²sin2∅/g

R = 15²sin(2×79.52)/9.8

R = 225(0.39)

R =87.75 m

∵ the building is = 11.025 m tall and the base of the building is 87.75m away from where the stone landed.

6 0

4 years ago

Middle C also known as "do" on the fixed do-solfege scale, is a note used when playing or singing music. The frequency of middle

saveliy_v [14]

Answer:

198.2m/s

Explanation:

Speed of a wave(v) is the product of the frequency of the wave (f) and its wavelength(¶).

Mathematically, v = f/¶

Given frequency of the middle C = 261.63Hz

Wavelength = 131.87cm

Converting this to meters we have;

131.87/100 = 1.32m

Speed of the sound = 261.63/1.32

Speed of the sound = 198.20m/s

Therefore the speed of sound for middle C is 198.2m/s

8 0

4 years ago

What kind of variation is there in the mechanical energy as the cart rolls down the ramp? Does this agree with your prediction?

Harlamova29_29 [7]

Answer:

Em₀ = U = m g h , Em_{f} = K = ½ m v²

Explanation:

When a car is on a ramp it has a certain amount of mechanical energy. At the highest point of the ramp the mechanical energy is fully potential given by

Em₀ = U = m g h

As part of this energy descends down the ramp, part of this energy is transformed into kinetic energy and has one part of each, even though the sum remains the initial energy

Em = K + U = ½ m v² + mg y

y <h

when it reaches the bottom of the ramp it has no height therefore there is no potential energy, all of it has been transformed into kinetic energy

Em_{f} = K = ½ m v²

This energy transformation is in the case that the friction force is zero.

If there is a friction force, it performs work against the low car, it is reflected in an increase in the internal energy (temperature) of the car. In this case the energy in the lower part is less than the initial one by a factor

$W_{nc}$ = - fr L

therefore the numeraire values of the velocity are lower, due to the energy lost by friction.

6 0

3 years ago

As more energy from fossil fuels and other fuels is released on Earth, the overall temperature of Earth tends to rise. Discuss h

BlackZzzverrR [31]

Answer:

processes are competitive and reach a thermal equilibrium where the absorbed energy is equal to the energy emitted, this is the equilibrium temperature of the planet.

Explanation:

The temperature of planet Earth is due to two main types of process, internal and external.

Internal processes are all chemical processes that occur that release heat into the environment or due to gases that trap heat on the planet, greenhouse effect

External processes is heating due to energy coming from the Sun. This includes direct heating of the surface by the absorption of energy and reflects of energy in different atmospheric layers.

These are the two terms that heat the Earth

In addition there are several processes so the planet loses energy,

* energy radiation to outer space that is a few degrees kelvin, for which there is a permanent emission

* endothermic processes that need to absorb heat to perform, this lowers the temperature of the system

* liquid (water) system that absorbs large amounts of heat to change state and temperature.

These processes are competitive and reach a thermal equilibrium where the absorbed energy is equal to the energy emitted, this is the equilibrium temperature of the planet.

Therefore it is impossible for the temperature to increase indefinitely since the emission would increase by decreasing the value

5 0

3 years ago