3. breakdown the practical uses of electromagnets in: [9 marks]
- circuit breakers
- electric bell
- relay switch in cars.

Ateam of astronauts is on a mission to land on and explore a large asteroid. in addition to collecting samples and performing experiments, one of their tasks is to demonstrate the concept of the escape speed by throwing rocks straight up at various initial speeds. with what minimum initial speed vesc will the rocks need to be thrown in order for them never to "fall" back to the asteroid? assume that the asteroid is approximately spherical, with an average density p 3.84 x108 g/m3 and volume v 2.17 x 1012 m3 recall that the universal gravitational constant is g 6.67 x 10-11 n m2/kg2

Free runners jump long distances and land on the ground or a wall. how do they apply newton’s second law to lessen the force of impact?

Which best represents the law of conservation of mass ?