Answer:
ΔT = 59.9 ° C
Explanation:
For this exercise the brake energy is totally converted into heat
Let's calculate the vehicle energy
K = ½ m v²
Let's reduce the units to the SI system
v = 30 mph (1609.34 m / mile) (1h / 3600s) = 13.41 m / s
Em = K = ½ 1200 13.41²
K = 1.079 105 J
All this energy is transformed into heat
Em = Q
The expression for heat is
Q = m 
ΔT
ΔT = Q / m
The specific heat of iron is = 450 J / Kg ºC
ΔT = 1,079 105 / (4.0 450)
ΔT = 59.9 ° C
solution:
Using Cartesian co-ordinate system
Final velocity =v= -4m/s
Initial velocity = u
Acceleration a = m/s²
Time (t).= 60s
By the first kinematical equation
V= u +at
U = v – at
=(-4)-(-3)(60)
176m/s
So, initial velocity was 176m/s
Answer:
7.7 km 26°
Explanation:
The total x component is:
x = 2.5 cos(35°) + 5.2 cos(22°) = 6.87
The total y component is:
y = 2.5 sin(35°) + 5.2 sin(22°) = 3.38
The magnitude is:
d = √(x² + y²)
d = 7.7 km
The direction is:
θ = atan(y/x)
θ = 26°
1. Changing from solid to a liquid is called melting / fusion and happen
at the melting/ fusion point.
Reason: melting point is a temperature at which a solid melt and converts into liquid by providing heat.
2. Changing from liquid to gas is called evaporation/boiling and happens at the evaporation/boiling point.
Reason. Evaporation is a process in which molecules from surface of liquid convert into gas.
3. Changing from a gas to a liquid is called condensation and happens at the condensation point.
Reason : In condensation process gas particles converts into liquid droplets.
4. Changing from liquid to a solid is called freezing and happens at the freezing point.
Reason : Freezing is a process that convert liquid into soilid state by decreasing temperature of that specific liquid,
Answer:
A hypothesis for the period of a pendulum is:
"The period of the pendulum varies with its length"
Explanation:
A hypothesis for the period of a pendulum is:
"The period of the pendulum varies with its length"
To test this hypothesis we can carry out a measurement of a simple pendulum keeping the angle fixed, in general the angle used is about 5º since when placing this value in radiand and the sine of this angle they differ little <5%. therefore measured the time of some oscillations, for example about 10 oscillations, changing the length of the pendulum to test the hypothesis.
If the hypothesis and the model used is correct, the relationship to be tested is
T² =(4π² /g) L
by making a graph of the period squared against the length if obtaining, os a line, the hypothesis is tested.
