Answer:
a) t = 4.14 s
b) Speed with which it hits the ground = 40.58 m/s
Explanation:
Using the equations of motion,
g = 9.8 m/s², y = H = 84 m,
Initial velocity, u = 0 m/s,
final velocity, v = ?
Total Time of fall, t = ?
a) y = ut + gt²/2
84 = 0 + 9.8t²/2
4.9t² = 84
t² = 84/4.9
t = 4.14 s
b) v = u + gt
v = 0 + (9.8 × 4.14)
v = 40.58 m/s
The answer is D. All of these
Answer:
150.8 J
Explanation:
The heat released by the copper wire is given by:
where:
m = 10.0 g is the mass of the wire
Cs = 0.377 j/(g.C) is the specific heat capacity of copper
is the change in temperature of the wire
Substituting into the equation, we find
And the sign is negative because the heat is released by the wire.
Explanation :
It is given that,
Potential energy, 
Power dissipated, 
We know that the power dissipated is given by :
I is the current passing through the phone.
or
I = 0.018 A
Hence, the current that passes through the phone is (1) 0.018 A.
Answer:
See below
Explanation:
You have to heat the calorimeter to 100 C from 20 C
this will take .20 kg * 390 j /kg-C * 80 C = <u>6240 j</u>
You have to heat the mass of water to boiling point (100 C ) from 20C
this will take
.50 kg * 4182 j/kg-C * 80 = <u>167,280 j </u>
AND you have to add enough heat to boil off .03 kg of water:
.03 kg * (2260000 j/kg-C ) =<u> 67,800 j</u>
<u />
Power = joules / sec = (6240 + 167280 + 67800) / 274.8 =<u> 878 watts </u>
<u />
<u>Your answer may differ just a bit for slightly different or rounded values of specific heat or heat of fusion for water .....</u>
