Answer:
b) It is impossible to tell without knowing the masses.
Explanation:
The temperature change of a substance when it receives/gives off a certain amount of heat Q is given by
where
Q is the amount of heat
m is the mass of the substance
Cs is the specific heat capacity of the substance
In this case, we have a hot piece of aluminum in contact with a cold piece of copper: the amount of heat given off by the aluminum is equal to the amount of heat absorbed by the copper, so Q is the same for the two substances. However, we see that the temperature change of the two substances depends on two other factors: the mass, m, and the specific heat, Cs. So, since we know only the specific heat of the two substances, but not their mass, we can't tell which object will experience the greater temperature change.
Answer:
The decelerating force is 
Solution:
As per the question:
Frontal Area, A = 
Speed of the spaceship, v = 
Mass density of dust, 
Now, to calculate the average decelerating force exerted by the particle:
(1)
Volume, 
Thus substituting the value of volume, V in eqn (1):
where
A = Area
v = velocity
t = time
(2)
From Newton's second law of motion:
Thus differentiating w.r.t time 't':
where
= average decelerating force of the particle
Now, substituting suitable values in the above eqn:
Answer:
Explanation:
Let L be the length of the wire.
velocity of pulse wave v = L / 24.7 x 10⁻³ = 40.48 L m /s
mass per unit length of the wire m = 14.5 x 10⁻⁶ x 10⁻³ / 2 x 10⁻² kg / m
m = 7.25 x 10⁻⁷ kg / m
Tension in the wire = Mg , M is mass hanged from lower end.
= .4 x 9.8
= 3.92 N
expression for velocity of wave in the wire
, T is tension in the wire , m is mass per unit length of wire .
40.48 L = 
1638.63 L² = 3.92 / (7.25 x 10⁻⁷)
L² = 3.92 x 10⁷ / (7.25 x 1638.63 )
L² = 3299.64
L = 57.44 m /s
Answer:
45km/hr
Explanation:
Total distance=450km
Total speed=50km/hr
Total time= distance/speed
=450/50
=9hrs
distance a=180km
speed a=60km/hr
Time a=180/60
=3hrs
Distance b=450-180=270km
Speed b=?
Time b=270/speed b
Total time=time a + time b
9=3+(270/speed b)
270/speed b =9-3
270/speed b =6
6*speed b =270
Speed b=270/6
Speed b=45km/hr
