What do understand by the efficiency of a machine? By using a block and tackel a man can raise a load of 720 N by an effort of 180 N. Find the mechanical advantage of the method.

Luke and carrie are driving down a straight section of the interstate at 70 mph in luke's new convertible. carrie is drinking a soda in the passenger seat. when she is done she tosses the bottle straight up in the air, just above the height of the car. what will happen to the bottle if air resistance is neglected? a. the bottle will land in carrie's lap. b. not enough information is given. c. the bottle will land on the interstate in front of the car. d. the bottle will land on the interstate behind the car.

An isotope undergoes radioactive decay by emitting radiation that has a –1 charge. what other characteristic does the radiation have?

Which of the following are used in an electrochemical cell? a. electrodes b. electrolyte c. terminals d. all of the above