motions and forces

what is a scalar quantity

a physical value that is completely described by its size or amount (magnitude) alone. It does not have a direction.

vector explained

a vector quantity is a physical value that has both magnitude (size) and a specific direction.

To describe a vector perfectly, you cannot just give a number and a unit; you must also state which way it is pointing or acting.

equation for speed

distance divide by time

velocity equation

displacemant divide by time

displacemant is direction in a specific dsitance 550m/s east

velocity is defined as the speed of an object in a given direction.

A toy car travels around a circular track at a completely constant speed of 2 m/s.

(a) Explain why the car's speed is constant but its velocity is changing.

) Speed is a scalar quantity and only depends on how fast the car is moving, which stays at 2 m/s (1 mark). However, velocity is a vector quantity that depends on both speed and direction. Because the car is moving in a circle, its direction is constantly changing, meaning its velocity must change (1 mark).

State what this changing velocity tells us about the car's movement. (1 mark)

Acceleration is a change in velocity over time, so an object changing direction is always accelerating!

what is the speed of anything being dropped

9.8m/s squared

what 2 ways do you calculate speed on a distance time graph

for constant speed do distance divide by time

for changing speed draw a tangent and find 2 points then do change in distance of these 2 points divided by change in time

on a velocity time graph how do you find the acceleration of a constant velocity

and how do you find velocity for a straight line—————-

change in velocity divide by change in time

straight line means gradient is 0 becuase velocity is constant so look at y axis and that is ur answer

in a velocity time graph how do you find ditance travelled

area under the curve

but for curved parts count the squares and estimate

what is newtons first law

a resultant forceis required to change the motion of an object

what is newtons second law

if a non zero resultant force acts on a object it will cause the object to accelerate

the size of the resultant force is directly proportional to the acceleration it causes

newtons third law and what it means

when 2 object interact, the forces they exert on each other are equal and opposite

if i was to push on a box with 100n it will exert 100n againt me too so we are both exerting 100n in opposite directions

what is inertia

Inertia is an object's natural tendency to resist any change in its state of motion or rest

• An object that is still will stay still unless a force pushes or pulls it.

• In motion: An object that is moving will keep moving at the same speed and in the same straight line unless an outside force stops or changes it.

• Mass matters: An object with more mass has more inertia, meaning it is harder to start moving or harder to stop (like a heavy train compared to a shopping cart