Answer : 6.3 g/cm3
Step by step explanation:
Density = mass/volume
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

We don't know that at all. The 3rd law says that the REaction is opposite and EQUAL to the action. We don't know where that "twice as much" comes from.
The rays of light coming from the Sun are parallel to each other, so when they are reflected by the concave piece of glass (which acts as a concave mirror) they converge into the focus of the mirror, which is

The radius of curvature of a concave mirror is twice its focal length, so in this case it is:
Answer:
(a)The work done by the man is -15.03J.
(b)The force exerted on the object is 127.4N.
Explanation:
Mass of the object pulled by the man is -13kg
Object is lifted 11.8 cm vertical with his teeth it means (displacement = +11.8cm = +0.118m)
Acceleration due to gravity is 
(a) <u>Calculating the work done</u>:
Work done = mgh
Where "m" is mass of an object, "g" is acceleration due to gravity and "h" is the displacement.


The work done by the man is -15.03J.
(b) <u>Calculating the force</u>:
Probably the man and the object are close to the exterior of the earth. If the rigidity required to maintained the object of consistent velocity interior the gravitational field of the earth is 
Thus the weight of the object is balanced by the force of the man's teeth on the object. That is
F = mg

F = 127.4N
The force exerted on the object is 127.4N.