Answer:
Explanation:
The acceleration of gravity is 9.8m/s^2.
So to calculate the time it will take to make the ball stop(which btw means the ball now reach its greatest height), use the formula V1=V0+at. V1 is the final velocity(which is 0), V0 is the starting velocity(which is 30m/s), and the a(cceleration) is 9.8m/s^2.
(You can ignore the fact "at" is -30 instead 30, it's because the directions two velocity travel are opposite. )
We can now know the time it takes to make the ball stop just by the gravitational force is about 3 sec.
Use another formula S=1/2at^2, to find out the S(height) is 1/2*9.8*3^2=44.1, which is approximately D.45m .
Answer:
stop, drop and roll.
Explanation:
This is because rolling on the ground can help put out the fire by depriving it of oxygen.
Answer: 5.72 x 10-3Ω
Explanation:
Hi, to answer this question, first we have to calculate the cross sectional area of the cable:
Diameter (D)=6.07 mm
Since: 1000mm = 1m
6.07mm/ 1000mm/m = 0.00607 meters
Area of a circle : π (d/2)^2
A = π (0.00607/2)^2= 0.000028937 m2
Resistance formula:
Resistance (R) = P(resistivity) L (length)÷A (cross sectional area )
Replacing with the values given:
R = (2.82x10-8 x 5.87) / 0.000028937
R = 5.72 x 10-3Ω
Feel free to ask for more if needed or if you did not understand something.
No work is done because the object needs to be moved. The formula for work is Work = Force x Distance.
Answer:
C. It is negative
Explanation:
Per Newton's second law, the net force is the mass times the acceleration:
∑F = ma
If the acceleration is negative, the net force is negative.
where f is the line frequency and p is the number of poles. Thus fewer poles makes it go faster.