Aturntable that spins at a constant 78.0 rpm takes 4.00 s to reach this angular speed after it is turned on. find its angular acceleration (in rad/s2), assuming it to be constant, and the number of degrees it turns through while speeding up. you may want to review (page) . for related problem-solving tips and strategies, you may want to view a video tutor solution of rotation of a bicycle wheel. part apart complete express your answer in radians per second squared. αα = 2.04 rad/s2 submitprevious answers correct set up: ω0=0. ω=(78.0rpm)(2πrad1rev)(1min60s)=8.1 7rad/s solve: ω=ω0+αt gives α=ω−ω0t=8.17rad/s−04.00s=2.04rad/s2 significant figures feedback: your answer 2.042 rad/s2 was either rounded differently or used a different number of significant figures than required for this part. part b express your answer in degrees.

a) 2.04 rad/sec² b) 936°

Explanation:

a) By definition, angular acceleration, is the rate of  change  of angular velocity, so we can express it as follows:

γ = (ωf -ω₀) / t

The turntable starts from rest, so ω₀ = 0

Now, as the answer is needed to be expressed in rad/sec², first of all, we need to convert ωf from rpm to rad/sec, as follows:

ωf = 78 rev/min. (1 min/60 sec) . ( 2π rad/ rev) = 13/5 π rad/sec

∴ γ = 13/5π / 4.0 rad/ sec² = 13/20 π rad/sec² = 2.04 rad/sec²

b) As the angular acceleration is assumed constant, we can use the kinematic equation for angular displacement, similar to the one used for linear displacement x, as follows:

θ = θ₀ + ω₀t + 1/2γt²

If we choose  θ₀ = 0°,  and we already know that ω₀ = 0, we finally have:

θ = 1/2 γ t²

Replacing by the values, we have:

θ = 1/2 . 13/20 π rad/sec² . (4.0)² sec² = 26/5 π rad

Converting to degrees, we have:

θ = (26/5) π  rad .(360º/2π rad) = 936º

a high pressure system is a dense air mass that is usually cooler and drier than the surrounding air. a low pressure system is a less dense air mass that is usually wetter and warmer than the surrounding air.

in general, areas that experience high atmospheric pressure also experience fair weather. low pressure systems can cause the formation of clouds and storms. air usually flows from areas of high pressure to areas of low pressure..