Which device requires an electric power supply?

Two friends, Al and Jo, have a combined mass of 168 kg. At an ice skating rink they stand close together on skates, at rest and

Keith_Richards [23]

Answer: 91.94 kg

Explanation: Supoose Al's mass is m. The combined mass is 168kg, so Jo's mass is 168 - m.

The Law of Conservation of Momentum states that when two objects collide, the total momentum of both objects before the collision is the same as the total momentum of both objects after the collision.

At the beginning, Al and Jo are united without movement, so their initial momentum is zero.

After the release of their hands, Al goes in one direction and Jo moves to the opposite direction. Suppose the direction Al is moving is positive. Conservation of momentum will be

$m_{1}v_{1}_{(f)}+m_{2}v_{2}_{(f)}=m_{1}v_{1}_{(i)}+m_{2}v_{2}_{(i)}$

where

index i referes to initial momentum

index f to final momentum

index 1 refers to Al

index 2 to Jo

Calculating:

$m(0.91)-[(168-m)(1.1)]=0$

$0.91m+1.1m-184.8=0$

$2.01m=184.8$

m = 91.94

Al has a mass of 91.94 kg.

6 0

2 years ago

I need help ASAP please............

aniked [119]

Answer:

A satellite orbiting earth 1

Your shoulder 3

f=m x a 2

A soccer ball 2

A magician 3

When you paddle 3

A picture 1

Earth 1

A rocket 1

A speed skater 2

Explanation:

Law 1 states an object at rest , stay at rest and an object in motion stays in motion unless acted on by another force.

Law 2 states that the acceleration of an object depends on its mass and force applied.

Law 3 states every action creates an equal and opposite reaction.

6 0

3 years ago

Covert 60 mph to SI mks units

Flauer [41]

26.82m/s

Explanation:

Given:

speed = 60mph

problem: convert to m/s

To solve this problem, we have to find the right and appropriate conversion factor which equals to 1 to multiply this unit with:

we are converting:

miles to meters

hours to seconds

1.609km = 1mile

1000m = 1km

60s = 1 min

60 min = 1hr

Now to convert from mph to m/s

60 x $\frac{mi}{hr}$ x $\frac{1.609km}{1mi} x \frac{1000m}{1km} x \frac{1hr}{60min} x \frac{1m}{60s}$

= 26.82m/s

learn more:

Conversion brainly.com/question/1548911

#learnwithBrainly

7 0

3 years ago

Which of the following would be useful to show the growth rate of plants at verying temperatures?

astraxan [27]

B or d most likely, because a frequency table you can show for example the amount of time the plant grew to 30 cm in 87 degree feirenhieght

3 0

2 years ago

Read 2 more answers

Tungsten has a temperature coefficient of resistivity of 0.0045 (c°)-1. a tungsten wire is connected to a source of constant vol

Murljashka [212]

Answer:

$131.1^{\circ}C$

Explanation:

The power delivered in the wire is given by:

$P=\frac{V^2}{R}$

where V is the voltage of the battery and R is the resistance of the wire.

Since the voltage of the battery is constant, we can rewrite this equation as follows:

$V^2 = PR=const.$ (1)

At the beginning, the initial resistance is $R_0$ , and the power delivered is $P_0$ . Later, when the temperature increases, the power becomes $P_1 = \frac{2}{3}P_0$ , and the new resistance is $R_1$ . Using (1), we can write