Studied by 8 peopleWhat unit is weight measured in?
Newtons ( N)
How to calculate the gravitational field strength, mass, and weight?
g = W/m
W = m * g
m = W / g
The gravitational field strength on earth
the gravitational field strength on earth is 9.8N/kg. So 1.0kg object is around 9.8N and an object with a mass of 100kg would have a weight of around 980N.
what is the difference between mass and weight?
Mass - typically measured in kg and is how much material is present
Weight - measured in newtons (N) and is the gravitational force on an object
Calculate the mass of someone who is 500N
500/9.8 =51.02kg
Calculate the weight of someone whose mass is 60kg
60 × 9.8 = 588N
is mass a scalar or vector quantity?
scalar
is weight a vector or scalar?
vector
is gravitational field strength vector or scalar?
vector
what is the gravitational field strength on the surface of the moon?
1.6kg
Why would your weight change even though your mass remains the same if you were on the moon?
Your mass does not change but your weight would because the gravitational field strength is 1/6 of that on the earth and so is the gravitational force.
what is the acceleration of free fall equivalent too?
gravitational field strength
N/kg = m/s²
calculate the weight of a 140g phone on the surface of the earth
140g = 0.14kg
0.14 × 9.8 = 1.372N
What are the units for gravitational field strength?
N/kg
what is the difference between a scalar and vector quantity
a scalar quantity only has a magnitude while a vector has both magnitude and direction
How do you calculate speed?
Speed = distance/time
v = s/t
how to calculate average speed?
average speed = total distance travelled / total time taken
calculate the speed of a car that travels 500m in 20s
v = s/t
v = 500/20
v= 25 m/s
A cyclist has an average speed of 5.0 m/s for 2.0 min. Calculate the total distance travelled?
s = v * t
s = 5.0 × 2.0 × 60
s = 600m
Velocity
speed in a given direction (vector)
explain why velocity can have a minus sign
it tells you that an object is traveling in the opposite direction. So a velocity of -280 m/s upwards is actually a velocity of 280 m/s downwards
Acceleration
change in velocity per unit time
what is this symbol ‘∆’?
the greek delta symbol which means ‘change in…’
how to calculate acceleration
a = ∆v / ∆t
∆v is the change in velocity
∆t is the change in time
what are the units for acceleration
m/s²
define density
how closely packed the particles are in a solid, liquid or gas
how to calculate the density
density = mass/volume
p = m/v
Why should your line of sight be perpendicular to the ruler?
When the ruler is nearer to the eye than the object being measured, the reading will change as the eye moves
meniscus
surface of most liquids bend up or down near the walls of the measuring cylinder
How long is the delay of reaction time?
0.2s
what is the density of water?
1.0g/cm³
what is force measured in?
Newtons (n)
How do you calculate resultant force?
force = mass x acceleration
what is a balanced force?
when there is no resultant force.
when there are at least 2 forces acting on an object and they are balanced, the object will be stationary or move at a constant speed
what is resultant force?
total of all forces added-up
how to find the density of an irregular object
measure the mass of the object on a balance. Pour enough water to submerge the object and record it as volume 1. Add the object into the water and record volume 2. Subtract volume 2 from 1 to find the volume of the object. Divide the mass by the volume to find the density.
what are the different scalar quantities?
distance, speed, time, mass, energy, temperature, volume
Note
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