Answer:
Explanation:
All the rest of the information is extraneous. The only 2 things you have to know are
d = 20 km
t = 8 minutes = 8/60 hours = 0.13333333
So the speed is s = d/t
s = 20/0.1333333 = 150 km/hour
Note: you have not specified what units the speed is. I suppose you could answer 20/8 = 2.5 km/min
Answer:
Explanation:
Capacitor of 0.75μF, charged to 70V and connect in series with 55Ω and 140 Ω to discharge.
Energy dissipates in 55Ω resistor is given by V²/R
Since the 55ohms and 140ohms l discharge the capacitor fully, the voltage will be zero volts and this voltage will be shared by the resistor in ratio.
So for 55ohms, using voltage divider rule
V=R1/(R1+R2) ×Vt
V=55/(55+140) ×70
V=19.74Volts is across the 55ohms resistor.
Then, energy loss will be
E=V²/R
E=19.74²/55
E=7.09J
7.09J of heat is dissipated by the 55ohms resistor
Answer:
current, only
Explanation:
current:I
voltage:U
resistance:R
formula: I=U/R
Increasing the battery cause the increasing in the voltage. Resistance does not normally change. And the current would increase.
Answer:
Newton's second law of motion can be formally stated as follows: The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.
Assuming you are looking for the acceleration a:
1.

2.

where T is the tension and a is the acceleration of the blocks. The acceleration of the two blocks and the acceleration of the pulley must be equal.
The torque on the pulley is given by:
3.

where

and

.
Combining the three equations: