B) in Physics, charge conservation is the principle that the total electric charge in an isolated system never changes. The net quantity of electrical charge, the amount of positive charge minus the amount of negative charge in the universe is always conserved.
Answer:
A baseball (m= 149g) approaches a bat horizontally at a speed of 40.2 m/s (90 mi/h) and is hit straight back at a speed of 45.6m/s (102mi/h). If the ball is in contact with the bat for a time of 1.10ms, what is the average force exerted on the ball by the bat ? Neglect the weight of the ball, since it is so much less than the force of the bat. Choose the direction of the incoming ball as the positive direction.
Explanation:
Use the impulse equation (a form of Newton's 2nd Law): FΔt = Δ(mv) where Δ means "change in"
The change in momentum is mBB(vf - vi) = (.150 kg)(-46.9 m/s - 40.5 m/s)
Divide this by the time interval and you get F exerted by the bat in Newtons.
Take care.
Answer:
3. 5.0N/kg
Explanation:
Gravitational field strength = gravitational force/mass of astronaut = 350N/70kg = 5.0N/kg
Answer:
The surface tension is 0.0318 N/m and is sufficiently less than the surface tension of the water.
Solution:
As per the question:
Radius of an alveolus, R = 
Gauge Pressure inside, 
Blood Pressure outside, 
Now,
Change in pressure, 
Since the alveolus is considered to be a spherical shell
The surface tension can be calculated as:
And we know that the surface tension of water is 72.8 mN/m
Thus the surface tension of the alveolus is much lesser as compared to the surface tension of water.
Answer: 3 m.
Explanation:
Neglecting the mass of the seesaw, in order the seesaw to be balanced, the sum of the torques created by gravity acting on both children must be 0.
As we are asked to locate Jack at some distance from the fulcrum, we can take torques regarding the fulcrum, which is located at just in the middle of the length of the seesaw.
If we choose the counterclockwise direction as positive, we can write the torque equation as follows (assuming that Jill sits at the left end of the seesaw):
mJill* 5m -mJack* d = 0
60 kg*5 m -100 kg* d =0
Solving for d:
d = 3 m.
