It was not the first time that a person who was in a few weeks ago, I
Answer:
4992 J
Explanation:
Force, F = 39 N
Distance, s = 128 m
Work done = force x distance
W = 39 x 128
W = 4992 J
Thus, the work done is 4992 J.
Answer:
3.26 secs
Explanation:
Diameter of sphere ( D )= 10 mm
T1 = 75°C
P = 1 atm
T∞ = 23°C
T2 = 35°c
Velocity = 10 m/s
<u>Determine how long it will take to cool the sphere to 35°C</u>
<em>Using the properties of copper and air given in the question</em>
Nu = 2 + (Re)^0.8 (Pr)^0.33
hd / k = 2 + ( vd/v )^0.8 (Pr)^0.33
∴ h ≈ 2594.7 W/m^2k
Given that :
(T2 - T∞) / ( T1 - T∞ ) = exp [ ( -hA / pv CP ) t ]
( 35 - 23 ) / ( 75 - 23 ) = exp [ - 2594.7 * 6 * t / 8933 * 387 * 10 * 10^-3 ]
= ln ( 12/52 ) = -1.466337069 = - 0.45032919 * t
∴ t ≈ 3.26 secs ( -1.466337069 / -0.45032919 )
Answer:
The correct answer will be-
1. Allows scientists to replicate experiments
2. Tests only one variable at a time
3. Plans how to record data so they can be published
Explanation:
A scientific experiment is performed to test the hypothesis which represents the limited explanation of the phenomenon.
The experiment is designed in a way that it test one variable at a time like the growth of plants. The experiment must be designed in a way that it can be replicated to reduce the error and repeated by other scientific persons to support the experiment. The design includes the plan for recording the results as it is one of the steps of the scientific method.
Thus, the selected options are the correct answer.
Controlled experiment is the type of experiment that involves changing only one variable at a time. Controlled experiment is subtly defined as an experiment which holds everything constant except one particular variable. This type of experiment allows only one variable to ever change at a given time
It depends on what skateboard. It will stop mainly because some skateboards need a hill or curvy platform to function.
