A man of mass 60kg dives vertically downwards into a pool from tower o...
**Average Resistance During Descent**
To find the average resistance offered by water during the man's descent, we need to consider the forces acting on him. During his descent, the forces acting on the man are:
1. Gravitational force (weight): Fg = mg, where m is the mass of the man and g is the acceleration due to gravity (9.8 m/s^2).
2. Buoyant force: Fb = ρVg, where ρ is the density of water, V is the volume of the man, and g is the acceleration due to gravity.
Since the man is completely submerged in water, the buoyant force is equal to the weight of the water displaced by the man. Therefore, Fg = Fb.
Using the given information, we can calculate the volume of the man:
V = m/ρ = 60 kg / 1000 kg/m^3 = 0.06 m^3
The buoyant force is then:
Fb = ρVg = 1000 kg/m^3 * 0.06 m^3 * 9.8 m/s^2 = 58.8 N
Since the buoyant force is equal to the gravitational force, the net force acting on the man during his descent is zero. Therefore, the average resistance offered by water during his descent is also zero.
**Rate of Acceleration Away from Side of Pool**
To find the rate at which the man accelerates away from the side of the pool, we can use the formula for power:
Power = Force * Velocity
The power developed by the man is given as 200 W, and the resistance of water for the swimmer's horizontal motion is 220 N. Therefore, we can write:
Power = Force * Velocity
200 W = 220 N * Velocity
Solving for velocity, we get:
Velocity = 200 W / 220 N = 0.909 m/s
Therefore, the rate at which the man accelerates away from the side of the pool is 0.909 m/s.
**Greatest Possible Speed**
To find the greatest possible speed the swimmer can reach, we need to consider the balance between the power developed by the swimmer and the resistance of the water.
The power developed by the swimmer is given as 200 W, and the resistance of the water is 220 N. The power developed is equal to the product of the force and velocity:
Power = Force * Velocity
Solving for velocity, we get:
Velocity = Power / Force
Velocity = 200 W / 220 N = 0.909 m/s
Therefore, the greatest possible speed the swimmer can reach is 0.909 m/s. This is the speed at which the power developed by the swimmer is equal to the resistance of the water. If the swimmer tries to swim faster, the resistance of the water will be greater than the power developed, and the swimmer will not be able to maintain that speed.
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