Answer:
Explanation:
Givens
Heat of Fusion = 2.05 * 10^5 J / kg watch the units.
Heat to actually melt the copper = 82 10^5 J
Formula
Mass of copper = Heat / Heat of Fusion
Solution
Mass of copper = 82*10^5 J / (2.05 * 10^5 J / kg)
Mass of copper = 40 kg
Notice that the kg is in the denominator of the second fraction. The rules of fractions would tell you the 1/1 / / 1 /kg . You take the right fraction and turn it upside down and multiply. 1 / 1 * kg/1 = 1* kg / 1*1 which is just kg.
Answer 40 kg of copper
O2 is considered 2 atoms because O2 is 2 oxygen atoms.
Answer:
26.2 m/s
Explanation:
We can find the speed of the cannonball just by analyzing its vertical motion. In fact, the initial vertical velocity is
(1)
where u is the initial speed and 
is the angle of projection.
We can therefore use the following suvat equation for the vertical motion of the ball:
where 
is the vertical velocity at time t, and 
is the acceleration of gravity. The time of flight is 3.78 s, so we know that the ball reaches its maximum height at half this time:
And at the maximum height, the vertical velocity is zero:
Substituting these values, we find the initial vertical velocity:
And using eq.(1) we now find the initial speed:
