In order to compare the two temperatures, we need to convert 20°F into Celsius. The formula we need to use is:
Substituting 20°F, we find
And this is less than 0°C, so the answer is
20°F is colder than 0°C.
The minimum initial velocity that the ball must have for it to reach the top of the hill is 21 m/s. The correct option is D.
<h3>What is mechanical energy?</h3>
The mechanical energy is the sum of kinetic energy and the potential energy of an object at any instant of time.
M.E = KE +PE
A boy is trying to roll a bowling ball up a hill. The friction is ignored. The ball must have to reach the top of the hill with a velocity. The acceleration due to gravity, g = 9.8 m/s²
The conservation of energy principle states that total mechanical energy remains conserved in all situations where there is no external force acting on the system.
M.E bottom of hill = M.E on top of hill
Kinetic energy + Potential energy = Kinetic energy + Potential energy
1/2 mu² + 0 = 0 + mgh
At the top of hill, the velocity will become zero. So, final kinetic energy is zero.
Substituting the values, we have
1/2 x u² = 9.8 x 22.5
u = sqrt [2 x9.8 x 22.5 ]
u= 21 m/s
Thus, the minimum initial velocity that the ball must have for it to reach the top of the hill is 21 m/s.
Learn more about mechanical energy.
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The kinetic energy should be 1,102.5 joules.
Answer:
91.017N
Explanation:
Parameters
L=4.67m, m=0.192kg, t = 0.794s, The pulse makes four trips down and back along the cord, we have 4 +4 =8 trips( to and fro)
so N= no of trips = 8, From Wave speed(V) = N *L/t , we have :
V= 8*4.67/0.794 = 47.0529 m/s.
We compute the cords mass per length, Let it be P
P = M/L = 0.192/4.67 = 0.04111 kg/m
From T = P * V^2 where T = Tension, we have
T = 0.04111 * (47.0529)^2
T = 91.017N.
The tension in the cord is 91.017N
Answer:
Acceleration is the change in velocity over the change in time = Δv/Δt. To do these problems, you need to find out how much the speed changed and over what period of time it changed.
Snail 1 changes from 4 cm/min to 7 cm/min in 3 minutes. Subtract the starting velocity (4 cm/min) from the ending velocity (7 cm/min) then divide by the time (3 min):
Snail 1 = (7 cm/min. - 4 cm/min)/(3 minutes) = ? (remember to put down the units)
Snail 2 changed from 7 cm/min. down to 1 cm/min. in 3 minutes
Snail 2 = (1 cm/min. - 7 cm/min.)/(3 min.) = ? (note that the acceleration is negative when you slow down)
I hope this helps you