P4-Explaining Motion Flashcards
A speed camera is set up in a 30mph (13.3m/s) zone. It takes two photographs 0.5 seconds apart. A car travels 6.3m between the two photographs. Was the car breaking the speed limit?
0.5\6.3m=no
What does the gradient of the time graph tell you?
Gradient=speed
What’s the difference between speed and velocity?
Speed is just how fast it’s going the direction isn’t important however velocity tells you the speed and direction
What is an interaction pair?
When an object applies force to the other it always experiences a force in return these two forces are called a interaction force
A man leans on the wall with a force of 50N. What can you say about this force?
It’s an apposing force
Explain what happens to the drag on a car as it speeds up?
The faster the car gets the bigger the drag gets to try and slow it down
Give two everyday examples where forces are balanced?
The reaction on a surface is a balanced force and a plane going at a steady speed
Find the momentum of a 78kg sheep moving at 5m/s
Momentum=mass x velocity
78kgX5m/s
If an object has a zero resultant force can it be moving?
No
Explain how air bags, crumple zones and seat belts reduce the risk of serious injury in a car crash?
Air bags- slow you down more slowly
Crumple zones- crumple on impact, increasing time taken for the car to stop
Seat belts- increasing time taken, reduces forces on chest
A crazy dog dragged a big branch 12m over the next door neighbours front lawn pulling with a force of 535n how much work done was on the branch?
Work done= force x distance
Why is the increase in an objects kinetic energy normally a bit less than the amount of work done?
Because energy is lost as heat because of friction and air resistance
Calculate the increase in gravitational potential energy when a box of weight 120n is raised vertically through 4.5m
G.P.E=weight x height
120 x 4.5
Find the speed of a partly chewed mouse which hobbles 3.5 metres in 35 seconds?
Distance divided by time=
3.6\35= 0.10
