Bhavika tries lifting the same object weighing 25 kg in different ways as shown here. She is standing on a 3 m tall platform. Which of these ways would require the least effort?
A 
B 
C 
D 
B
Ans 2:
Class : Class 10
Single pulley does not provide any mechanical advantage, it only changes the direction of force while an inclined plane provides mechanical advantage. This means the efforts required to life the same amount of load on an inclined plane is lesser than that by a single pulley. (Pulley provides mechanical advantage only if we use more than one pulley).Lesser the inclination more is mechanical advantage and lesser the effort. That means the correct answer should be 'D'
Ans 5:
Class : Class 5
B because if we use a rope to pull it will take a lot of effort, if we take a small or large inclined plane it will also take more effort because the load will slip down but in pulley we have to only pull the rope