PROBLEM
If a ball travels around a circle of radius 4 m in 1.5 minutes, what is the angular spee of the ball?
a) 45π radians /s
b) 452π radians /s
c) 30π radians /s
d) 1.52π radians /s
STEP 1
1. The radius of the circle is 4m.
2. The ball completes the circle in 1.5minutes.
3. We need to find the angular speed in radians per second.
STEP 2
1. Calculate the circumference of the circle.
2. Determine the time in seconds.
3. Calculate the angular speed.
STEP 3
The circumference of a circle is given by the formula C=2πr, where r is the radius. Here, the radius r=4m.
C=2π×4 C=8πm
STEP 4
Convert the time from minutes to seconds. We know that 1minute=60seconds.
1.5minutes=1.5×60seconds 1.5minutes=90seconds
SOLUTION
Angular speed is defined as the angle in radians covered per unit time. Since the ball covers the entire circumference, it travels 2π radians in 90seconds.
Angular speed=90seconds2πradians Angular speed=45πradians per second The angular speed of the ball is:
45πradians per second
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