Which of the following is a secondary pollutant

Aman throws a football straight into the air. as it rises, it slows down. which type of energy is the football gaining?

For the car in the picture ,in which direction is the normal force? -into the screen -down -out of the screen -up

The period of a pendulum varies directly as the square root of the length of the pendulum and inversely as the square root of the acceleration due to gravity. find the period when the length is 144 cm and the acceleration due to gravity is 980 cm per second squared, if the period is 7pi seconds when the length is 289 cm and the acceleration due to gravity is 980 cm per second squared.