# Mass in relation to Tangential Force

• to819
In summary, the problem involves a child exerting a tangential force on a disk-shaped merry-go-round with a radius of 2.20 m. The merry-go-round starts at rest and acquires an angular speed of 0.0870 rev/s in 4.50 s. Using the formula torque=I*alpha, the mass of the merry-go-round can be found to be 21.665 kg. There was an initial mistake in the formula used, but it was corrected after seeking help. The angular acceleration must be in radians per second squared to use the formula correctly.
to819

## Homework Statement

A child exerts a tangential 42.4 N force on the rim of a disk-shaped merry-go-round with a radius of 2.20 m. If the merry-go-round starts at rest and acquires an angular speed of 0.0870 rev/s in 4.50 s, what is its mass?

## Homework Equations

t=I$$\alpha$$
I=.5mr2

## The Attempt at a Solution

42.4=.5*2.22*.8087*m
m=21.665

Would the above be correct? I'm hesitant about entering it as I only have one more attempt to solve this problem. If not would converting the revolutions per second into radians per second be the right thing to do? Anyone see anything I'm missing? Any help is appreciated. Thank you.

Last edited:
There is mistake in your formula.

Firstly, torque formula is $$\tau = F.R.sin(\theta) (\theta$$ is angle between F and R)

Besides, torque can be found by using this formula: $$\tau = I. \alpha (\alpha$$ is angular acceleration)

p/s: what is '0.8087' number in your calculation? I don't get it :(

Ah, thank you for that. That number was me mistyping 0.0870. Should I convert the angular speed to radians per second before I solve for angular acceleration or leave it as is?

Try doing dimensional analysis. If you convert to radians, you'll get an angular acceleration in radians/s^2. If you leave it as is, you'll get an acceleration in revs/s^2. Both are correct, but the formula torque=I*alpha requires that alpha be in radians per second squared.

Solved for it correctly thanks to the help of both of you. Thank you both.

## 1. What is the formula for calculating tangential force?

The formula for calculating tangential force is F = m x a, where F is the tangential force, m is the mass, and a is the tangential acceleration.

## 2. How does mass affect tangential force?

Mass has a direct relationship with tangential force. This means that as mass increases, tangential force also increases, assuming all other variables remain constant.

## 3. How does tangential force affect an object's motion?

Tangential force is responsible for causing an object to move in a circular or rotational motion. Without tangential force, an object would continue to move in a straight line.

## 4. Can tangential force be negative?

Yes, tangential force can be negative. This means that the direction of the force is opposite to the direction of the object's motion.

## 5. How is tangential force related to centripetal force?

Tangential force and centripetal force are both necessary for circular motion. Tangential force causes the object to move along the tangent of the circle, while centripetal force acts towards the center of the circle, keeping the object in its circular path.

Replies
2
Views
2K
Replies
2
Views
2K
Replies
1
Views
1K
Replies
1
Views
1K
Replies
1
Views
1K
Replies
44
Views
5K
Replies
17
Views
2K
Replies
3
Views
8K
Replies
10
Views
2K
Replies
9
Views
2K