motion (topic 5) Flashcards
calculate the acceleration of the car between C and D
describe the motion of the car between B and C
constant speed/velocity of 12 m/s
calculate the distance travelled between A and C
describe how the forces acting on the skydiver vary as they fall (4)
- weight acts downwards
- initially air resistance is negligible/zero
- as the speed of the skydiver increases, air resistance increases
- terminal velocity is reached when the weight of the skydiver is equal to the air resistance
explain how a parachute allows the skydiver to land safely (4)
- when the parachute is opened, the air resistance acting on the skydiver increases (so air resistance is greater than weight)
- this causes the skydiver to decelerate
- as the skydiver decelerates, air resistance decreases
- when weight is equal to the air resistance again, a new lower terminal velocity is reached
calculate Jacks speed between 16 and 28 minutes
convert 1,300 km/h to m/s
explain why the car reaches a top speed (3)
- as the car accelerates, the air resistance increases
- reducing the resultant force acting on the car
- when the thrust is equal to the drag forces, the acceleration is zero and the car travels at a constant speed
calculate the distance travelled by the athlete during the period of acceleration at the start of the race
this roller coaster reaches a top speed of 26 m/s in 22.5 m, calculate the acceleration of the roller coaster at the start of the ride
the mass of a passenger is 70kg, calculate the force exerted on the passenger during the initial acceleration 15m/s^2
state the resultant force acting on the roller coaster cart at 25 s, give a reason for your answer (3)
- 0 N
- the roller coaster is travelling at constant speed, therefore zero acceleration
- with no acceleration, the resultant force is zero as given by F = m x a
calculate the distance travelled by the roller coaster between 10 s and 20 s
describe the motion of the stone from A to B (3)
- stone leaves the water surface at -6 m/s at 0 s
- stone decelerates and reaches the top of the bounce at 0.6 s
- stone accelerates downwards and hits the water again at 1.2 s
calculate the maximum height reached by the stone above the water surface
- distance travelled is equal to the area
- area = 0.5 x 6 x 0.6 = 1.8 m