Which statements describe ways in which heat can be generated?

by rubbing two sticks together, enough heat can be generated to start a camp fire.
1) heat energy is generated by ice when it is melting.
2) heat can be created when tires roll on paved highway roads on a long road trip.
3) gravity generates heat by pulling solar energy toward earth's surface.
4) water creates heat energy when it condenses to form clouds.
5) burning broken tree limbs and other yard scraps creates heat energy.

Aspecial electronic sensor is embedded in the seat of a car that takes riders around a circular loop-the-loop ride at an amusement park. the sensor measures the magnitude of the normal force that the seat exerts on a rider. the loop-the-loop ride is in the vertical plane and its radius is 23 m. sitting on the seat before the ride starts, a rider is level and stationary, and the electronic sensor reads 740 n. at the top of the loop, the rider is upside down and moving, and the sensor reads 370 n. what is the speed of the rider at the top of the loop?

The difference between two numbers is 15. when twice the smaller number is subtracted from three times the larger number, the difference is 58.what is the larger number?

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?