Answer:
(a) θ1 = 942.5rad, (b) θ2 = 13195 rad
Explanation:
(a) Given
ωo = 0 rad/s
ω = 3600rev/min = 3600×2(pi)/60 rad/s
ω = 377rad/s
t1 = 5s
θ1 = (ω + ωo)t/2
θ1 = (377 +0)×5/2
θ1 = 942.5 rads
(b) ωo = 377rad/s
ω = 0 rad/s
t2 = 70s
θ2 = (ω + ωo)t/2
θ2 = (377 +0)×70/2
θ2 = 13195 rad
Answer:
a) a = 0.477 m/s^2
b) u = 0.04862
Explanation:
Given:-
- The rotational speed of the turntable N = 33 rev/min
- The watermelon seed is r = 4.0 cm away from axis of rotation.
Find:-
(a) Calculate the acceleration of the seed, assuming that it does not slip. (b) What is the minimum value of the coefficient of static friction between the seed and the turntable if the seed is not to slip
Solution:-
- First determine the angular speed (w) of the turntable.
w = 2π*N / 60
w = 2π*33 / 60
w = 3.456 rad/s
- The watermelon seed undergoes a centripetal acceleration ( α ) defined by:
α = w^2 * r
α = 3.456^2 * 0.04
α = 0.477 m / s^2
- The minimum friction force (Ff) is proportional to the contact force of the seed.
- The weight (W) of the seed with mass m acts downwards. The contact force (N) can be determined from static condition of seed in vertical direction.
N - W = 0
N = W = m*g
- The friction force of the (Ff) is directed towards the center of axis of rotation, while the centripetal force acts in opposite direction. The frictional force Ff = u*N = u*m*g must be enough to match the centripetal force exerted by the turntable on the seed.
Ff = m*a
u*m*g = m*a
u = a / g
u = 0.477 / 9.81
u = 0.04862
11,000 m = 11 km
11 km/s over 380,000km
380,000 / 11 = 34545.4 seconds
34545.4 / 60 = 575.7 minutes
The object is called a meteor because it is producing Streak of light and has not yet struck earth.
<h3><u>Explanation:</u></h3>
A meteoroid is a celestial object which is very smaller than an asteroid. These objects are produced as a collision impact from mars or moon and float freely in space without any specific orbit. When they come inside the Earth's gravitational field, they are attracted by the Earth's gravity to Earth's crust. These objects in Earth's atmosphere are called meteors. As they travel through Earth's atmosphere, they do face a huge friction from Earth's atmosphere which let them burn and that is visible as the tail of the meteor.
Most of them are so small that they are burnt away in the atmosphere. But some are bigger and they reach the Earth's surface and are called as meteorites.
Sample Response: How can magnetic and electric fields be demonstrated?
