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19 Cards in this Set
- Front
- Back
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What is the dif between scalar and vector quantities? |
Scalar quantities only has magnitude .vector quantities have both magnitude and direction. Scalar:speed,mass,enerģy,time. Vector:displacement,velocity,acceleration |
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F=ma formula |
F( in N)=m(kg)xa(m/s^2) Why |
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1.why velocity increases immediately after being dropped? 2.why does it reach uniform veocity after a shtime? |
1.It increased sped immediately as v=0,no air resistance is there.there is a resultant force which is the gravitational force acting downwards on the object,hence acceleration.since velocity increases,this means the object accelerates due to resultant forces.this shows tht weight is geater than air resistance. 2.as velocity increases,resultant force increases.after a short time the air resistance opposes the motion,becomes equal to the weight.this will cause the acceleration =0.hence,object moves down at uniform speed. |
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Newtons 3rd law of motion |
1.states tht for every action,there is a opposite reaction |
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Mass and inertia? |
Mass is defined as the amt of matter in an substance. Inertia is the measure of the reluctance of and object to move. |
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Gravity formula |
Gratitatinal fielstrength is defined as the gravitational force acting per unit mass of an object. g= gravitaional force/mass G's SI unit: N/kg or m/s^2 |
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Dif between mass and weight? |
Mass:amt of mattter in an obj Not dependant on location Scalar quantity Measured using beam balance SI is kg Weight:amt of grav f acting on an obj Dependant on location and grav field Vector quantity Measured using spring balance SI unit is N |
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Density formula? |
Density=mass/volume p=m/v
SI unit:kg/m^3 |
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Average density formula? |
Av dens=total mass/total volume p=m/v |
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Average density formula? |
Av dens=total mass/total volume p=m/v |
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When parachutist first jump off the plane? |
>weight is greater than air resistance >resultant force is downwards >hence,acceleration is downwards as F=ma >velocity increases |
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When velocity increases? |
>Air resistance increases >resultant force decreases >hence acceleration decreases(F=ma) |
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Free falling? |
>when parachutist frst jump of the plane,weight is greater than air resistance >when velocity increases... >air resistance will increase util it is equivalent to weight. |
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Openin parachute desc
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When parachute opens fully, 1.air resistance will be much greater than weight 2.resultant force is upwards. 3.causes the man to decelerate 4.velocity decreases.
When velocity decreases, 1.air resistance decreases 2.resultant force decreases 3.falls with decreasing deceleration
Air resistance will decrease until it is equivalent to weight. 1.resultant force = 0N 2.hence,acceleration is 0 m / s^2 3.move with constant velocity When the man lands on the ground 1.velocity decreases til zero. |
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Wht to take note on vector diagram? |
1.direction 2.Newton,arrows,angles,cm 3.scale(100n;1cm) 4.label 'resultant force' |
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Direction of force?how to do?oh no! |
2 degrees from 850N vector |
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Weight formula? |
Weight is the amount of gravity acting on an object
SI unit:N newton W=m x g W(N)=m(kg) x g(N/kg) |
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Weight formula? |
Weight is the amount of gravity acting on an object
SI unit:N newton W=m x g W(N)=m(kg) x g(N/kg) |
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Constant speed of the falling parachutist: |
As speed increases,air resistance increases until it is equivalent to weight,at which point acceleration is zero as resultant force is zero as F=ma.hence parachutist falls with constant speed. |
