Answer:
Speed of the wave in the string will be 3.2 m/sec
Explanation:
We have given frequency in the string fixed at both ends is 80 Hz
Distance between adjacent antipodes is 20 cm
We know that distance between two adjacent anti nodes is equal to half of the wavelength
So 

We have to find the speed of the wave in the string
Speed is equal to 
So speed of the wave in the string will be 3.2 m/sec
Answer: It’s 98,000
Explanation: Just did it on apex
Answer:
A. 42.3 revolution per minute
B. Centripetal Force
Explanation:
20 g = 0.02 kg
5 cm = 0.05 m
Let g = 9.8 m/s2
A.The friction force acting on the eraser is the product of normal force and its coefficient:

For the eraser to begin slipping, its centripetal acceleration must win over the acceleration created by friction force, which is

We can calculate the angular velocity from this:

where r = 0.05 is the radius of rotation, which is distance from the center to the eraser


If it spins and angle of 4.43 rad per second then for every minute (60 seconds) it would spin an angle of 4.43 * 60 = 265.6 rad/min
Since 1 revolution is 2π rad, then in a minute it would spin 265.6 / 2π = 42.3 revolution/minute
B. The force responsible for making the eraser go faster while the turntable is spinning up would be the centripetal force.
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2: a machine can help us find important information
3: a machine can help us transport from a place to another