Give reasons: 1. We use tongs to a catch a burning piece of a coal.
2. We use a pulley to draw water from a well.
3. A second class lever multiplies the effort more than other levers.

Explanation:

1) 1 : to Prevent a burning we use tongs

2:it can burn our skin hoa it's help

2) 1: because pulley helps in water draw from a well

3) 1: second class lever has mechanical advantage more than one as load is in between fulcrum an effort making the effort arm longer than the load arm

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27