Select the correct answer.

If the earth shrank until its radius were only one-quarter its present size without changing its mass what would a 20 n object w

Dahasolnce [82]

Basing on the information given, we can calculate the new weight of the object by the following given:current weight = 20 Ng = 10m/s2

20N/4 = 5N

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5 0

3 years ago

A kettle is rated at 1 kW, 220 V. Calculate the working resistance of the kettle.

Anna [14]

Explanation:

Power of electric kettle, P = 1 kW

Voltage, V = 220 V

(a) Electric power is given by the formula as follows :

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

R is resistance

$R=\dfrac{V^2}{P}\\\\R=\dfrac{(220)^2}{10^3}\\\\R=48.4\ \Omega$

(b) When connected to a 220 V supply, it takes 3 minutes for the water in the kettle to reach boiling point.

Energy supplied is given by :

$E=P\times t$

P is power, $P=\dfrac{V^2}{R}$

$E=\dfrac{V^2}{R}t\\\\E=\dfrac{(220)^2}{48.4}\times 180\\\\E=180000\ J\\\\E=180\ kJ$

5 0

3 years ago

give an example of situation in which an automobile driver can have a centripetal acceleration but no tangential speed

Mars2501 [29]

There is no need for tangential acceleration when moving in a circle at a constant speed.

<h3>What is centripetal acceleration?</h3>

centripetal acceleration refers to the speed at which a body moves through a circle. Due to the fact that velocity is a vector quantity (i.e., it has both a magnitude, the speed, and a direction), when a body travels in a circle, its direction is constantly changing, which causes a change in velocity, which results in an acceleration.

<h3>Which is an example of centripetal acceleration?</h3>

Centripetal acceleration occurs when you spin a ball on a string above your head. A car experiences centripetal acceleration when it is being driven in a circle. Additionally, a satellite in orbit around the Earth experiences centripetal acceleration.

To know more about tangential acceleration :

brainly.com/question/14993737

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6 0

1 year ago

3. An athlete makes a long jump and follows a projectile motion. Air resistance is negligible. Which one of the following statem

yulyashka [42]

Answer:

Option (b) is correct.

Explanation:

The motion under the influence of gravity is called projectile motion.

The acceleration due to gravity is constant through out the motion and it is always acting downwards.

When an athlete jumps and follow the projectile path, it always have the same horizontal velocity as there is no acceleration in the horizontal direction.

Also he has the vertical acceleration constant which is equal to the acceleration due to gravity and acts towards the center of earth.

Option (b) is correct.

6 0

3 years ago

A sound source emits 20.0 W of acoustical power spread equally in all directions. The threshold of hearing is 1.0 × 10-12 W/m2.

ahrayia [7]

Answer:

0.0018 W/m²

Explanation:

Power and intensity are related as:

$I=\frac{P}{4\pi r^2}$