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3 years ago

When a rigid body rotates about a fixed axis, all the points in the body have the same

Physics

1 answer:

timama [110]3 years ago

5 0

Hi there!

$\large\boxed{\text{Angular acceleration.}}$

For a rigid body rotating about a fixed axis, its angular characteristics ⇒ angular acceleration and velocity are constant throughout.

However, its LINEAR velocities/accelerations differ because of the following relationships:

v = ωr

a = αr

Thus, a point closer to the axis of rotation has a smaller linear velocity or acceleration compared to a point along the edge.

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Select the situation for which the torque is the smallest.

alina1380 [7]

Answer:

e. The torque is the same for all cases.

Explanation:

The formula for torque is:

τ = Fr

where,

τ = Torque

F = Force = Weight (in this case) = mg

r = perpendicular distance between force an axis of rotation

Therefore,

τ = mgr

Here,

m = 200 kg

r = 2.5 m

Therefore,

τ = (200 kg)(9.8 m/s²)(2.5 m)

τ = 4900 N.m

Here,

m = 20 kg

r = 25 m

Therefore,

τ = (20 kg)(9.8 m/s²)(25 m)

τ = 4900 N.m

Here,

m = 8 kg

r = 62.5 m

Therefore,

τ = (8 kg)(9.8 m/s²)(62.5 m)

τ = 4900 N.m

Hence, the correct answer will be:

e. The torque is the same for all cases.

6 0

3 years ago

Help on finding kinetic energy??

Jobisdone [24]

Trick question? In order to have kinetic energy, an object must be moving. Therefore, in this case, kinetic energy would be 0. If it were asking about potential energy, it would be a different story.

8 0

3 years ago

Read 2 more answers

How does the size of arctic foxes ears help to keep them warm in a cold environment

DochEvi [55]

artic foxes have thick white fur to keep them warm and also for camouflage in the snow they have small ears to keep the snow out of their ears so that they can hear better they also have thick fur lining and a thick pad on their feet this stops the paws from getting cold and they have short legs so then the body weight can be spread making it easier for the animal to not sink in the snow in the summer the artic fox turns brown to help make the fox invisible when people are hunting in the long grass

3 0

3 years ago

A girl coasts down a hill on a sled, reaching level ground at the bottom with a speed of 7.4 m/s. The coefficient of kinetic fri

Amanda [17]

Answer: 62.22 meters

Explanation:

Two solve this, we need to know first how the Sled interact with the snow. While the Sled runs over the snow, the snow opposes to it movement, this is call friction. Frictions creates is a force that goes against any movement and is caused by the interaction between surfaces.

Friction can be calculated using the following equation:

Friction's Force (Ff) = m*N

Where m is the Frictions coficient and N is call Normal, which is a force created by the contact between any weight and a surface. Because the sled is and the surface are totally horizontal, the Normal is equal to the Sled's Weight.

So for this case, we can calculate the Friction's Force:

Ff = 0.045 * 735 N

Ff = 33,07 N

This force will cause a negative acceleration the Sled causing it to slow down and finally stop. To know this accelaration we can use the following equation:

Force (F) = Mass (m) * Accelaration (a)

Looking for the accelaration:

Acceleration (a) = F / M

As a side note:

Mass (M) = F / a (1)

Where we know that F is equal to our Friction Force (Ff) and the Mass for the girl and the Sled can be obtained using the previous equation (1) like this

Girl and sled Mass (M) = 735 N / (9.81 m/s)

M = 74,92 Kg

This is posible, because the Girl and The Sled are aplying a Force on the ground equal to 735 N. The accelartion for their mass is the gravity

Now, with the mass we can found the Accelaration caused by friction:

Acceleration (a) = Ff / M

Accelaration (a) = 33,07 N / 74,92 Kg

a = 0,44 $m/s^{2}$

To know how far the Sled travel we can use the following equation:

$V_{f} ^{2} = V_{0} ^{2} + 2ax$

Where Vf is the Final Velocity, which is when the sled finally stops (Vf = 0), Vo is the Initial Speed of the Sled equal to 7.4 m/s and a is equal to the negative accelaration that causes the friction.

$(0)^{2} = (7.4 m/s)^{2} + 2(-0,44)x$