Answer:
The minimum compression is 
Explanation:
From the question we are told that
The mass of the block is 
The spring constant is 
The coefficient of static friction is 
For the the block not slip it mean the sum of forces acting on the horizontal axis is equal to the forces acting on the vertical axis
Now the force acting on the vertical axis is the force due to gravity which is mathematically given as

And the force acting on the horizontal axis is force due to the spring which is mathematically represented as

where x is the minimum compression to keep the block from slipping
Now equating this two formulas and making x the subject

substituting values we have


The statement that is true of cooling down after physical activity is that you should cool down for about 5 to 10 minutes after being physically active.
Answer:
b. 0.20 m/s.
Explanation:
Given;
initial mass, m = 0.2 kg
maximum speed, v = 0.3 m/s
The total energy of the spring at the given maximum speed is calculated as;
K.E = ¹/₂mv²
K.E = 0.5 x 0.2 x 0.3²
K.E = 0.009 J
If the mass is changed to 0.4 kg
¹/₂mv² = K.E
mv² = 2K.E

Therefore, the maximum speed is 0.20 m/s