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3 years ago

Kenna has a mass of 30 kilograms. What's her weight in newtons? Assume that acceleration due to gravity is 9.8 N/kg.

Physics

1 answer:

astra-53 [7]3 years ago

5 0

Answer:

294 N

Explanation:

The weight of an object is the gravitational force exerted by the Earth on the object.

The direction of this force is always towards the Earth's centre, while the magnitude is given by:

$W=mg$

where

W is the weight

m is the mass of the object

g is the acceleration due to gravity

Here we have:

m = 30 kg is the mass of the object

g = 9.8 N/kg is the acceleration due to gravity

So, the weight of the object is

$W=(30)(9.8)=294 N$

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If eight water waves pass an ocean buoy each minute, and successive wave crests are 20 m apart, find the wave speed:____________

Llana [10]

Answer:

The wave speed is calculated below:

Explanation:

Given,

number of waves passed per minute = 8

time period = 1 minute = 60 s

distance between successive wave crests = 20 m

waves passing interval per second = $\frac{8}{60}$ $s^{-1}$

Now,

wave speed = 20 m × $\frac{8}{60}$ $s^{-1}$

= $\frac{8}3}$ m/s

= 2.67 m/s

Hence the wave speed is 2.67 m/s.

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3 years ago

Space debris left from old satellites and their launchers is becoming a hazard to other satellites. (a) Calculate the speed of a

Pie

Answer:

Part a)

$v = 7407.1 m/s$

Part b)

$v_{rel} = 1.05 \times 10^4 m/s$

Explanation:

Part a)

As we know that orbital velocity at certain height from the surface of Earth is given as

$v = \sqrt{\frac{GM}{R+h}}$

here we know that

$M = 5.98 \times 10^{24} kg$

$R = 6.37 \times 10^6 m$

$h = 900 km = 9.0 \times 10^5 m$

now we have

$v = \sqrt{\frac{(6.67 \times 10^{-11})(5.98 \times 10^{24})}{6.37 \times 10^6 + 9.0 \times 10^5}}$

$v = 7407.1 m/s$

Part b)

When a loose rivet is moving in same orbit but at 90 degree with the previous orbit path then in that case the relative speed of the rivet with respect to the satellite is given as

$v_{rel} = \sqrt{2} v$

$v_{rel} = 1.05 \times 10^4 m/s$

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3 years ago

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An ignious rock's color is mainly determined by its silica content

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3 years ago

A ball is released from rest at a height of 10 m and falls freely to the

ElenaW [278]

Answer:

The new kinetic energy would be 16 times greater than before.

Explanation:

Kinetic energy is found using this formula:

KE = 1/2mv²
where KE = kinetic energy (J), m = mass (kg), and v = velocity (m/s)

We can see that kinetic energy is directly proportional to the square of the velocity, meaning that if the speed was increased by 4 times, then the kinetic energy would get increased by a factor of 16.

The velocity just before the ball hits the ground can be found by the equation:

√(2gh)

Let's substitute h = 10 m and h = 40 m into this formula.

√(2g(10))
√(2g(40))

We can see that the velocity increases by a factor of 4 (10 m → 40 m).

Therefore, this means that the kinetic energy would also be increased by a factor of (4)² = 16. Thus, the answer is D) The new kinetic energy would be 16 times greater than before.

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3 years ago