The first thing you should know for this case is that density is defined as the quotient between mass and volume.
d = m / v
We have two states:
State 1:
d1 = 1.20 g / l
v1 = 1.02 × 106 l
State 2:
v2 = 1.09 × 106 l
Since the mass remains constant, then:
m = d1 * v1
Then, the density in state two will be:
d2 = m / v2
Substituting the value of the mass we have:
d2 = (d1 * v1) / v2
Substituting the values:
d2 = ((1.20) * (1.02 * 10 ^ 6)) / (1.09 * 10 ^ 6) = 1.12 g / l
answer:
The density of the heated air in the balloon is 1.12 g / l
Gravitational potential energy :)
These stars fuse helium into carbon just like the sun.
Answer:
The ball will reach the ground in 0.8s
Option C
Explanation:
Given:
- Takes t = 0.8 s for ball to reach ground when thrown horizontal from top of a building.
Find:
If it had been thrown with twice the speed in the same direction, it would have hit the ground in how many second.
Solution:
- We know that the amount of time taken to hit the ground is determined by the vertical distance i.e height at which it is thrown. The displacement of ball from top is given by:
S_y = S_o + V_i,y*t + 0.5*g*t^2
- We know that the S_o = height of the building.
We also know that the ball os thrown horizontally; hence, y-component of initial velocity is zero. V_y,i = 0
0 = h + 0 + 0.5*g*t^2
- Hence, the time taken t is:
t = sqrt ( 2h / g)
- The time taken to reach the ground is independent of the initial speed. Hence, the ball will reach the ground in 0.8s .
Space surrounding magnet is called the magnetic field. In this field we can encounter magnetic force. Magnet attraction occurs when poles are unlike and is caused by magnetic force. It means that poles should have opposite values.
