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3 years ago

A bicyclist travels 30 km in 2 hours, what is their average speed?

Physics

1 answer:

Mamont248 [21]3 years ago

3 0

Explanation:

average speed = total distance ÷ total time taken

=30÷2 = 15 km/h

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A typical electric refrigerator has a power rating of 500 Watts, which is the rate (J/s) at which electrical energy is supplied

Goshia [24]

Answer:

The rate of heat removed from inside the refrigerator is 300 watts.

Explanation:

By the First Law of Thermodynamics and the definition of a Refrigeration Cycle, we have the following formula to determine the rate of heat removed from inside the refrigerator ( $\dot Q_{L}$ ), in watts:

$\dot Q_{L} = \dot Q_{H}-\dot W$ (1)

Where:

$\dot Q_{H}$ - Rate of heat released to the room, in watts.

$\dot W$ - Rate of electric energy needed by the refrigerator, in watts.

If we know that $\dot Q_{H} = 800\,W$ and $\dot W = 500\,W$ , then the rate of heat removed from inside the refrigerator is:

$\dot Q_{L} = \dot Q_{H}-\dot W$

$\dot Q_{L} = 300\,W$

The rate of heat removed from inside the refrigerator is 300 watts.

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3 years ago

When a ball rolls down a hill, what energy conversion occurs?

Ludmilka [50]

Answer:

Explanation:

When a ball rolls down a hill, Potential Energy Conversion takes place to Kinetic Energy.

8 0

3 years ago

The magnetic field of a solenoid depends upon n, which represents select one:

Lady bird [3.3K]

The number of loops

8 0

3 years ago

The hydraulic oil in a car lift has a density of 8.30 102 kg/m³. The weight of the input piston is negligible. The radii of the

denpristay [2]

Answer:

(a) $F_i=68.58\ N$

(b) $F_i=69.903\ N$

Explanation:

Given:

density of hydraulic oil, $\rho=830\ kg.m^{-3}$

radius of input piston, $r_i=6.3\times 10^{-3}\ m$

radius of output plunger, $r_o=0.125\ m$

force to be supported, $F_o=27000\ N$

(a)

Condition:The bottom surfaces of piston and plunger at the same level.

According to Pascal's law the pressure of a fluid is exerted equally in all directions against the walls of its container.

Mathematically:

$\frac{F_i}{A_i} =\frac{F_o}{A_o}$

putting respective values

$\frac{F_i}{\pi\times r_i^2} =\frac{27000}{\pi\times r_o^2}$

$\frac{F_i}{\pi\times (6.3\times 10^{-3})^2} =\frac{27000}{\pi\times 0.125^2}$

$F_i=68.58\ N$

(b)

Condition:The bottom surface of the output plunger is 1.30 m above that of the input piston.

Given:

$h=1.3\ m$

Now,

$P_i=P_o+\rho.g.h$

$\frac{F_i}{\pi\times (6.3\times 10^{-3})^2} =\frac{27000}{\pi\times 0.125^2} +830\times 9.8\times 1.3$

$F_i=69.903\ N$

7 0

3 years ago

What is a point on a standing wave that appears to be stationary.

777dan777 [17]

It's the node of the standing wave.

5 0

3 years ago