The friction of air causes a vertical retardation equal to 10 % of the...
Friction of air and its effect on maximum height and time taken to return to the ground
Effect of air friction on maximum height:
- The given problem states that the friction of air causes a vertical retardation equal to 10% of the acceleration due to gravity.
- This means that the net acceleration of the object will be (1-10/100) times the acceleration due to gravity, which is 9 ms^-2.
- Using the kinematic equation, we can find the maximum height reached by the object, which is given by H = u^2/2g, where u is the initial velocity of the object.
- Since the object is thrown upwards, u is positive and we can take it as u = 10 ms^-1 (assuming no other external forces acting on the object).
- Substituting the values, we get H = 50 m.
- Now, if we assume that there is no air friction, the maximum height would have been given by H = u^2/2g = 50 m (since u and g are constant).
- Therefore, the decrease in the maximum height due to air friction is given by (50-50)/50 x 100% = 10%.
- Hence, the correct answer is option (c) 10%.
Effect of air friction on time taken to return to the ground:
- The time taken to reach the maximum height is given by t = u/g = 1 s (since u and g are constant).
- In the absence of air friction, the time taken to return to the ground would have been equal to the time taken to reach the maximum height, which is 1 s.
- However, in the presence of air friction, the object experiences a vertical retardation which reduces its upward velocity and increases the time taken to return to the ground.
- But, since the retardation is only 10% of the acceleration due to gravity, the increase in time will be negligible and the time taken to return to the ground will be almost the same as in the absence of friction.
- Hence, the correct answer is option (a) almost same as in the absence of friction.
The friction of air causes a vertical retardation equal to 10 % of the...
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