The hang time of the ball is 4.08 s
Explanation:
The ball is in free fall motion: this means that it is acted upon gravity only, so its acceleration is the acceleration of gravity,
downward (the negative sign refers to the downward direction).
Since this is a uniformly accelerated motion, we can solve the problem by using the following suvat equation:
where
v is the final velocity
u is the initial velocity
a is the acceleration
t is the time
First we calculate the time it takes for the ball to reach the maximum height, where the velocity is zero:
v = 0
Substituting:
u = +20 m/s
we find t
The motion of the ball is symmetrical, so the total time of flight is just twice the time needed to reach the maximum height, therefore:
Learn more about free fall:
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Answer:
Hot water rises and cold water sinks is a model of thermal energy transfer by conduction.
Distance = speed x time. The total speed is 30 + 60 = 90km/h and the total time taken is 15 + 15 = 30 minutes. Therefore, you do 90 x 30 = 2700km
Answer = 2700km
Answer:
Explanation:
v² = u² + 2as
s = (v² - u²) / 2a
s = (29.88² - 6.73²) / (2(5.22))
s = 81.1802203065...
s = 81.18 m
While pushing a refrigerator up a ramp, there would be less friction to overcome if you used a dolly because of the wheels. So the efficiency of the ramp would be greater with the use of the dolly.
<u>Explanation:</u>
The ramp provides for a wedge setup, so when the refrigerator is being pushed up the ramp, the friction on the ramp would equally distributed to the refrigerator when pushed wholly as the friction applied is a product of the coefficient of friction with the Normal reaction of the weight in contact with the surface.
Therefore, when the dolly is used, the surface in contact becomes divided and thus, the friction applied would become less due to though coefficient of friction remains the same, the normal reaction of the weight becomes small and so does the applied friction. Therefore, efficiency of the ramp increases as the friction is less and work done is more.
