Final answer:
The phonograph record turns at an angle of 0.30π rad in 0.20 s.
Step-by-step explanation:
To calculate the angle turned by the phonograph record in 0.20 s, we can use the formula:
Angle = (angular velocity) x (time)
Given that the record rotates at 45 rpm, we first convert this to radians per second:
45 rpm = 45 * 2π/60 = 3π/2 rad/s
Now we can substitute the values into the formula:
Angle = (3π/2 rad/s) x (0.20 s) = 0.30π rad
Therefore, the record turns at an angle of 0.30π rad in 0.20 s.