The block's maximum speed when the total energy is doubled will be 80cm/s.A pendulum motion is an example of oscillation.
Oscillation is the periodic or repeating oscillation of a measure around a central value or between two or more states, usually in time
The formula for the maximum speed of the oscillation is found as;
[tex]\rm v_{max}=2 \pi fA \\\\[/tex]
The energy of the oscillation is found as;
[tex]E= = \frac{KA }{2}[/tex]
When the total energy is doubled the velocity will be 4 times the velocity.
[tex]v'_{max}=4 v_{max} \\\\ v'_{max}=4 \times 20 \\\\ v'_{max}=80 \ cm/sec[/tex]
Hence the block's maximum speed when the total energy is doubled will be 80cm/s.
To learn more about the oscillation refer to the link;
https://brainly.com/question/16976640
