Answer:
d. 37 °C
Explanation:
= mass of lump of metal = 250 g
= specific heat of lump of metal = 0.25 cal/g°C
= Initial temperature of lump of metal = 70 °C
= mass of water = 75 g
= specific heat of water = 1 cal/g°C
= Initial temperature of water = 20 °C
= mass of calorimeter = 500 g
= specific heat of calorimeter = 0.10 cal/g°C
= Initial temperature of calorimeter = 20 °C
= Final equilibrium temperature
Using conservation of heat
Heat lost by lump of metal = heat gained by water + heat gained by calorimeter

Answer:

Explanation:
Let m is the mass of both cars. The first car is moving with speed v and the other car is moving with speed 2v. The only force acting on both cars is the centripetal force.
For faster car on the road,

v = 2v

..........(1)
For the slower car on the road,
............(2)
Equation (1) becomes,


So, the frictional force required to keep the slower car on the road without skidding is one fourth of the faster car.
Answer:
see explanation below
Explanation:
Given that,
500°C
= 25°C
d = 0.2m
L = 10mm = 0.01m
U₀ = 2m/s
Calculate average temperature

262.5 + 273
= 535.5K
From properties of air table A-4 corresponding to
= 535.5K 
k = 43.9 × 10⁻³W/m.k
v = 47.57 × 10⁻⁶ m²/s

A)
Number for the first strips is equal to


Calculating heat transfer coefficient from the first strip


The rate of convection heat transfer from the first strip is

The rate of convection heat transfer from the fifth trip is equal to


Calculating 

The rate of convection heat transfer from the tenth strip is


Calculating

Calculating the rate of convection heat transfer from the tenth strip

The rate of convection heat transfer from 25th strip is equal to

Calculating 

Calculating 

Calculating the rate of convection heat transfer from the tenth strip

Answer:
<em>c. The astronaut does not need to worry: the charge will remain on the outside surface.</em>
<em></em>
Explanation:
The astronaut need not worry because <em>according to Gauss's law of electrostatic, a hollow charged surface will have a net zero charge on the inside.</em> This is the case of a Gauss surface, and all the charges stay on the surface of the metal chamber. This same principle explains why passengers are safe from electrostatic charges, in an enclosed aircraft, high up in the atmosphere; all the charges stay on the surface of the aircraft.
Given that,
Mass of each washer = 4.9 g
We need to calculate the mass of two washers in kg
Using conversion of unit
Mass of each washer 
So, Mass of two washers is

Put the value of m


If 4 washer are attached to the spring
We need to calculate the applied force on the car
Using formula of force

Put the value into the formula


Hence, (i), The mass of two washers is 0.0098 kg.
(ii). The applied force on the car is 0.192 N.