Choose the correct answer :
12-A car of mass 1200 kg is moving with a velocity 20 m/s .If the driver used the brakes and the speed of the car decreased to 8 m/s within 6 sec , then the average force acting on the car during this period and its direction is ……………..
1
1
a) 2400 N in the same direction.
2
b) 2400 N in the opposite direction.
3
c) 1200 N in the same direction.
4
d) 1200 N in the opposite direction.
تصحيح
Choose the correct answer :
11-If there are two persons falling from different heights , the person who falls from the largest height will be harmed more than the other , and this is due to……………
1
1
a) Increasing the time of impact
2
b) Decreasing the time of impact
3
c) Increasing the change in the velocity
4
d) Increasing air resistance
تصحيح
Choose the correct answer :
10-The collision of a large truck with a wall is more destructive than the collision of a small car although they have the same velocity , that is due to in case of small car …………..
1
1
a)by increasing mass the force of collision will increase.
2
b) by increasing time of impact the force of collision will decrease.
3
c) by decreasing mass the force of collision will decrease.
4
d) by increasing acceleration the force of collision will increase.
