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3 years ago

Please help with these questions ASAP. If correct I will give brainliest.

Physics

1 answer:

rusak2 [61]3 years ago

7 0

answer

1)the direction is from the body of a high temperature to a body at a low temperature

2)at the melting point and boiling point because the heat given is used to break down the forces holding the particles together so that they can change their state

3)In a gas because the particles of gases are held by weak forces thus have large intermolecular spaces between the particles while the solids are in a fixed position

4)heat is transferred to another body if they experience different temperatures

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Please Help!!! An engine takes 3,000 J from a hot reservoir and expels 2,400 J to a cold reservoir. What is the thermal efficien

Murljashka [212]

Answer:

80%

Explanation:

Thermal efficiency is a measure of the extent to which a heat engine is able to convert to other form. It is measure in percentage.

Thermal efficiency = $\frac{E_{out} }{E_{in} }$ × 100%

Where $E_{in}$ is the input energy and $E_{out}$ is the output energy.

Given that: $E_{in}$ = 2400 J and $E_{out}$ = 3000 J, therefore:

Thermal efficiency = $\frac{2400}{3000}$ × 100%

= 80%

The thermal efficiency of the engine is 80%.

4 0

4 years ago

if a cyclist is travelling a road due east at 12km/h and a wind is blowing from south-west at 5km/h. find the velocity of the wi

slamgirl [31]

Answer:

The velocity of wind with respect to cyclist is $-15.5 \widehat{i} - 3.5 \widehat{j}$ .

Explanation:

speed of cyclist = 12 km/h east

speed of wind = 5 km/h south west

Write the speeds in the vector form

$\overrightarrow{vc} = 12 \widehat{i}\\\\overrightarrow{vw} = - 5 (cos 45 \widehat{i} + sin 45 \widehat{j})\\\\\overrightarrow{vw} =-3.5 \widehat{i} - 3.5 \widehat{j}$

The velocity of wind with respect to cyclist is

$\overrightarrow{vw} =-3.5 \widehat{i} - 3.5 \widehat{j}\overrightarrow{v_(w/c)} = \overrightarrow{vw}-\overrightarrow{vc}\\\\\overrightarrow{v_(w/c)} = - 3.5 \widehat{i} - 3.5 \widehat{j} - 12 \widehat{i}\\\\\overrightarrow{v_(w/c)} =-15.5 \widehat{i} - 3.5 \widehat{j}$

7 0

3 years ago

Pulsars are neutron stars that emit X rays and other radiation in such a way that we on Earth receive pulses of radiation from t

stira [4]

Answer:

(a) $a_{c} = 5.41\times 10^{9} m/s^{2}$

(b) $a_{t} = 2.99\times 10^{- 5} m/s^{2}$

Given:

Time period of Pulsar, $T_{P} = 33.085 ms == 33.085\times 10^{- 3} s$

Equatorial radius, R = 15 Km = 15000 m

Spinning time, $t_{s} = 9.50\times 10^{10}$

Solution:

(a) To calculate the value of the centripetal acceleration, $a_{c}$ on the surface of the equator, the force acting is given by the centripetal force: