# math

i asked this question before but didn't really get a particular answer.
A merry-go-round is rotating at the constant angular speed of 3 RPM counterclockwise. The platform of this ride is a circular disk of radius 24
feet.
(a) If θ = 34 degrees, what are your xy coordinates after 4 minutes?
(b) If θ = 20 degrees, what are your xy coordinates after 45 minutes?
(c) If θ = −14 degrees, what are your xy coordinates after 6 seconds?
(d) If θ = -2.1 rad, what are your xy coordinates after 2 hours and 7 seconds?

1. 👍
2. 👎
3. 👁
1. still no indication of what θ means. If it is the angle through which the wheel has rotated, then when θ=34°
(x,y) = (r cosθ, r sinθ) = (19.9,13.42)

But the rotation speed and time already tell you how far the wheel has gone, so who needs θ?

If θ is the angle when the rotation starts, then after a whole number of minutes, the wheel is back where it started. For
(c) the wheel has rotated 6/60 * 3 * 360 = 108° so add that to the initial value of -14°, so use 96° for your coordinates.

Once you decide what θ means for this problem, then it's just plug and chug. Until then, you're doomed.

1. 👍
2. 👎
👤
oobleck
2. If theta is measured counterclockwise from the x axis then
x= R cos theta and y = R sin theta

1. 👍
2. 👎
👤
Damon
3. Maybe theta here is angle off horizontal ?

1. 👍
2. 👎
👤
Damon

## Similar Questions

1. ### Physics

A merry-go-round with a a radius of R = 1.95 m and moment of inertia I = 192 kg-m2 is spinning with an initial angular speed of ω = 1.41 rad/s in the counter clockwise direection when viewed from above. A person with mass m = 63

2. ### physics

At a playground, a 20-kg child sits on a spinning merry-go-round, as shown from above in (Figure 1) . The merry-go-round completes one revolution every 6.2 s, and the child sits at a radius of r=1.8m. a. What is the force of

3. ### Physics

A merry-go-round is a common piece of playground equipment. A 2.4 m diameter merry-go-round with a mass of 300 kg is spinning at 22 rpm. John runs tangent to the merry-go-round at 5.0 m/s, in the same direction that it is turning,

4. ### Physics

A child sits on a rotating merry-go-round, 2.19 m from its center. If the speed of the child is 2.32 m/s, what is the minimum coefficient of static friction between the child and the merry-go-round that will prevent the child from

1. ### Physics

A brave child decides to grab onto an already spinning merry‑go‑round. The child is initially at rest and has a mass of 24.5 kg. The child grabs and clings to a bar that is 1.60 m from the center of the merry‑go‑round,

2. ### Physics

8. When a person stands on a rotating merry go round, the frictional force exerted on the person by the merry go round is (A) greater in magnitude than the frictional force exerted on the person by the merry go round (B) opposite

3. ### Physics

A 23-kg boy stands 3 m from the center of a frictionless playground merry-go-round, which has a moment of inertia of 180 kg m2. The boy begins to run in a circular path with a speed of 0.6 m/s relative to the ground. (a) Calculate

4. ### Physics Inertia : Merry-go-round

A playground merry-go-round of radius 1.96 m has a moment of inertia 335 kg m2 and is rotating at 12.3 rev/min. A child with mass 43.1 kg jumps on the edge of the merry-go-round. What is the new moment of inertia of the

1. ### Physics

2) A child sits on a merry-go-round, 1.5 meters from the center. The merry-go-round is turning at a constant rate, and the child is observed to have a radial acceleration of 2.3m/s^2. How long does it take for the merry-go-round

2. ### PHYSICS ---HELP!

A 3.6 m diameter merry-go-round is rotating freely with an angular velocity of 0.78 rad/s. Its total moment of inertia is 1700 kg\m^2. Four people standing on the ground, each of mass 62 kg, suddenly step onto the edge of the

3. ### Physics

Suppose you observe your friend (mass 66.6 kg) stand at the very edge of a motionless merry-go-round (modelled as a thin disk with moment of inertia 5.7 kg m 2). At some point, your friend walks around and along the edge at a

4. ### Physics

A playground merry-go-round made in the shape of a solid disk, has a diameter of 2.63 m and a mass of 353.9 kg. Two children, each of mass 30.5 kg, sit on opposite sides at the edge of the platform. Approximate the children as