Why is it easier to open the lid of a can by using a spoon as shown in Fig.? Class 9
Why is it easier to open the lid of a can by using a spoon as shown in Fig.? Class 9
Question 1.
Why is it easier to open the lid of a can by using a spoon as shown in Fig.? (Page 135) Class 9
Answer:
When a spoon is used to open a can lid, it acts as a Class I lever - the rim of the can is the fulcrum, effort is applied at the spoon's handle, and load is the lid. The effort arm (handle) is much longer than the load arm. From MA = effort arm / load arm, MA > 1. This means the force applied on the lid is much greater than the force applied by the hand, making it easy to pry open the lid.
Question 2.
Why do you push an object closer to scissors (fulcrum) when you want to cut an object which is hard? (Page 135) Class 9
Answer:
Scissors are a Class I lever with fulcrum at the pivot. When the object is placed close to the fulcrum, the load arm d2 decreases, so MA = d1/d2 increases. A higher MA means the cutting force on the hard object is much greater than the effort applied by the hand, making it easier to cut. If the object were placed far from the fulcrum, the load arm would be large, MA would be small, and cutting would be harder.