Physics unit 1 Flashcards
What is a force?
The push or pull on an object with mass which causes it to change its velocity
What is the SI unit for force?
Newtons
What is the difference between contact and non contact forces?
Contact forces need objects to be physically touching in order to act, non contact forces act over a distance
What is speed?
The distance covered per unit time. It is measured using the formula S=D/T. The SI unit is m/s
What is the difference between balanced and unbalanced forces?
Balanced forces are equal in size and opposite in direction, whereas unbalanced forces aren’t. Balanced forces do not cause a change in motion whereas unbalanced forces can change the shape, speed or direction of an object. When forces are balanced, the resultant force is 0N.
How is mass measured?
In Kilograms (kg)
How is weight measured?
In Newtons (N)
What is the equation for weight?
W=m*gravity (g)
What is the gravity on Earth?
9.8 m/s^2
What is the difference between mass and weight?
mass is the amount of matter in an object and weight is the effect of gravity on that mass
What is a scalar?
A scalar is a quantity that only has size
Examples:
-Distance
-Speed
-Mass
-Energy
What is a vector?
A quantity that has size and direction
Examples:
-displacement
-velocity
-acceleration
-force
-weight
What is displacement?
How far the object is from the original distance
What is distance?
How far an object travels. The SI unit is metres (m)
What is velocity?
How fast an object travels in a given direction
What is the equation for velocity?
Velocity=displacement/time
What is a resultant force?
The net force/overall effect of all the forces acting on an object
What is a resultant vector?
The combination of 2 or more single vectors.
What is Newton’s third law?
Every action has an equal and opposite reaction. When 2 objects interact, they exert equal and opposite forces on each other. The forces are acting on different objects. It explains how objects are able to move
How do you calculate resultant force?
If forces are acting in the same direction, they are added. If they are acting in opposite directions, they are subtracted and if they are perpendicular the resultant can be found using a scale drawing.
what is acceleration?
the rate of change in velocity. This could be an object speeding up, slowing down or changing direction. Acceleration is a vector quantity. it is measured in m/s^2.
what is the formula for acceleration
acceleration (m/s^2)=change in velocity (m/s)/time (s)
-to calculate the change in velocity you subtract the initial velocity from the final velocity
What is a negative acceleration (an object slowing down) called?
deceleration
how does acceleration affect air resistance?
as objects speed up, air resistance increases
What is newton’s first law
an object’s motion will not change unless acted upon by an unbalanced force (a non-zero resultant force)
What is inertia
the tendency of objects to continue in their state of motion
What does it mean if the resultant force is 0N
The forces are balanced and the object is in equilibrium. The object will continue stationary if it is still and an object in motion will continue moving at the same velocity
What happens if the resultant force is not 0N
The forces are unbalanced. A stationary object will accelerate in the direction of the resultant force. An object in motion will also accelerate in the direction of the resultant force
What is a gradient
the steepness of the slope at any point. On a straight line, the gradient is constant. On a curved line, the gradient changes at every point.
The gradient can be positive (sloping upwards), negative (sloping downwards) and zero (horizontal)
How do you calculate the gradient?
change in (triangle) y/ change in x
to calculate the gradient we need to know the coordinates of the start and the end
