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4 years ago

A skateboarder, just learning to use a half pipe as shown below, drops in off the top of

Physics

1 answer:

kramer4 years ago

4 0

Answer:

Energy was lost as frictional energy. Hence when trying to move up to the top for the second time, the skateboarder was unable to do so.

The others provided additional energy to make up for the lost energy by dending their knees

Explanation:

According to law of conservation of energy, energy can niether be created nor destroyed but can change its form.

Here kinetic energy of skate boarder was converted into frictional energy and lost in the surroundings(energy was not destroyed but simply changed its form to energy of particles in the air). She was therefore unable to reach to the top the second time.

Other skateboarders faced the same, but the added energy to their movement by converting energy stored in their bodies to their kinetic energies. They were therefore abole to reach to the top.

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At baseball practice, Mason and Alfredo both picked up the same bat and neither would let go until one of them had it for himsel

Illusion [34]

Answer:

Option B. O because the net force was 5 N in Alfredo's direction

Explanation:

To know the the correct answer to the question given above, we shall determine the net force acting on the bat. This can be obtained as follow:

Force of pull by Mason (Fₘ) = 15 N

Force of pull by Alfredo (Fₐ) = 20 N

Net force (Fₙ) =?

Fₙ = 20 – 15

Fₙ = 5 N in Alfredo's direction

From the calculation made above, we can see that the net force is 5N in Alfredo's direction. This is the reason why Alfredo end up having the bat.

7 0

3 years ago

A skater slides across the ice with an initial velocity of 5.0 m/s. She slows 10 points

zvonat [6]

Explanation:

Given that,

The initial velocity of a skater is, u = 5 m/s

She slows to a velocity of 2 m/s over a distance of 20 m.

We can find the acceleration of skater. It is equal to the rate of change of velocity. So, it can be calculated using third equation of motion as follows :

$v^2-u^2=2as$

a = acceleration

$a=\dfrac{v^2-u^2}{2s}\\\\a=\dfrac{(2)^2-(5)^2}{2\times 20}\\\\a=-0.525\ m/s^2$

So, her acceleration is $0.525\ m/s^2$ and she is deaccelerating. Also, her initial velocity is given i.e. 5 m/s.

7 0

3 years ago

A hollow spherical shell has mass 8.20 kg and radius 0.220 m. It is initially at rest and then rotates about a stationary axis t

Likurg_2 [28]

Answer:

8.91 J

Explanation:

mass, m = 8.20 kg

radius, r = 0.22 m

Moment of inertia of the shell, I = 2/3 mr^2

= 2/3 x 8.2 x 0.22 x 0.22 = 0.265 kgm^2

n = 6 revolutions

Angular displacement, θ = 6 x 2 x π = 37.68 rad

angular acceleration, α = 0.890 rad/s^2

initial angular velocity, ωo = 0 rad/s

Let the final angular velocity is ω.

Use third equation of motion

ω² = ωo² + 2αθ

ω² = 0 + 2 x 0.890 x 37.68

ω = 8.2 rad/s

Kinetic energy,

$K = \frac{1}{2}I\omega ^{2}$

K = 0.5 x 0.265 x 8.2 x 8.2

K = 8.91 J

6 0

3 years ago

What forces are acting when you try to crack<br> an egg in your palm(will give brainliest)

Aleks [24]

Answer:

Kinetic energy in your palm

4 0

3 years ago

What is the momentum of a 1400 kg car traveling at 25 m/s?

sveticcg [70]

<h2>Hello</h2>

The answer is:

$35000Kg.\frac{m}{s}=35000N$

Momentum is the quantity of movement of an object, and it's calculated using the mass and the velocity of the object. Momentum is expressed by the following formula:

$p=m*v$

Where:

$m=mass\\v=velocity$

So, calculating we have:

$p=m*v=1400Kg*\frac{25m}{s}=35000Kg.\frac{m}{s}=35000N$

Remember,

$1N=1Kg.\frac{m}{s}$

Have a nice day!

5 0

3 years ago

Read 2 more answers