Class 9 | Motion | exercises question 7,8,9&10 | скачать в хорошем качестве

Class 9 | Motion | exercises question 7,8,9&10 |

motion chapter exercises question 7 ) A ball is gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of 10 m s-2, with what velocity will it strike the ground? After what time will it strike the ground? 8) The speed-time graph for a car is shown in Fig. 8.12  (a) Find how far does the car travel in the first 4 seconds. Shade the area on the graph that represents the distance travelled by the car during the period. (b) Which part of the graph represents uniform motion of the car? 9) State which of the following situations are possible and give an example for each of these: (a) an object with a constant acceleration but with zero velocity (b) an object moving with an acceleration but with uniform speed. (c) an object moving in a certain direction with an acceleration in the perpendicular direction 10) An artificial satellite is moving in a circular orbit of radius 42250 km. Calculate its speed if it takes 24 hours to revolve around the earth solution : Given, the radius of the orbit = 42250 km Therefore, circumference of the orbit = 2*π*42250km = 265571.42 km Time is taken for the orbit = 24 hours Therefore, speed of the satellite = 11065.4 km.h-1 The satellite orbits the Earth at a speed of 11065.4 kilometers per hour.