calculate the magnitude and direction of the resultant of 2 forces A and B acting on a point object
A=3N along y axis
B=2N across x axis
45 degree angle in between them


300g of water at 20 degrees celsius is placed in a freezer.
How much heat energy must be removed in order to freeze it completely?


Help is needed!!

For your first question, have a sketch, I have told you earlier. Now, to find the resultant, use the head to hail method. In that method, you draw a polygon (here a triangle) from the point object and add the second force where the first ends. The resultant will be the line joining the point object to the end of the last force.

For the second one, use



Q is the amount of heat energy
m is the mass of the water
c is the specific heat capacity of water
delta theta is the change in temperature.

However, that doesn't end here. You now have liquid water at 0 degrees Celsius. You have to find the energy to freeze it. This is given by



Q is the amount of heat
m is the mass of the water
L is the specific latent heat of solidification of water

Add both Q s to get the total energy required.