The speed of the ball is always zero and the acceleration is always -g when it reaches the top of its motion. This is because when the ball is free, only gravity acts on it which is always downwards, hence g is the net acceleration and it is always negative. However the velocity does not direction change instantly, negative acceleration first slows down the ball with a positive velocity, until that point the ball keeps moving up, then the ball velocity becomes zero just before changing direction and becoming negative after which the ball will now go down along gravity. Hence the ball velocity is zero at the top (neither going up nor down). Mathematically this can be seen as velocity is the integration of acceleration.
We need a and we have m and F . Now a = f÷m so therefore a = 4,9 ÷ 0,5 which is 0,98 metres per cubic second
320 Kilometers = 198.8 miles
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1 gallon of Petrol = 40 Miles
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198.8/40 = 4.95 Gallons of Petrol
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Cost of Petrol = 3:20 (per Gallon) x 4.95 Gallons = 15.84
Answer:
Explanation:
Let T be the tension in the swing
At top point 
where v=velocity needed to complete circular path
r=distance between point of rotation to the ball center=L+\frac{d}{2} (d=diameter of ball)
Th-resold velocity is given by 
To get the velocity at bottom conserve energy at Top and bottom
At top 
Energy at Bottom 
Comparing two as energy is conserved
Answer:
Explanation:
A) When a dipole is placed in an electric field , it experiences a torque equal to the following
torque = p x E = p E sinθ , where θ is angle between direction of p and E .
It will be zero if θ = 0
or if both p and E are oriented in the same direction.
It is the stable orientation of dipole.
If θ = 180° ,
Torque = 0
In this case both p and E are oriented in opposite direction .
It is the unstable orientation of the dipole because if we deflect the dipole by even small angle , it goes back to most stable orientation due to torque acting on it by electric field.
