For counting x you use simple equation for the distance covered by the object when it moves with constant velocity:
that gives you 20m after 1st second, 40 m after 2nd second, 60 m after 3rd second and so on.
For counting y you have to use the equation for the distanced covered by the object moving with constantly accelerating velocity (symbols refering to vertical movement):
that gives you 5m after 1st second, 20m afters 2nd second, 45m after 3rd second and so on.
Add minus signs before y positions to receive graph presenting the movement of the ball.
So the points are: P1=[20,-5], P2=[40,-20], P3=[60,-45] and so on... Pn=[x,y].
Answer: The poker stick should have low thermal conductivity and high specific heat.
Explanation: For a poker stick that is non flammable, it should have some properties which will not let it heat up faster.
Two properties that satisfy the poker stick are:
- Specific heat
- Thermal conductivity
Specific heat is defined as the amount of heat require to raise the temperature of a mass M by 1 °C. More the specific heat, more amount of heat will be required to raise the temperature of a substance.
Thermal conductivity is defined as the ability of a substance to conduct heat. More thermal conductivity means that the substance will get hot faster as it will conduct more amount of heat.
So, for a substance that should not conduct more heat like the poker stick must have high specific heat and low thermal conductivity.
The correct option is D.
During hurricane, the most important thing is to get people out to safety in order to save their lives. Training the community about safety evacuation route is by far the better idea because it provide immediate safety from the natural hazard. The second idea is not a good one at all, because if food are stocked in every house in the community, the food will be destroyed alongside other things during the hurricane.
It all depends on the SIZE of the balloon.
If the balloon is made of really tough rubber, and it holds the helium in the same volume as the solid iron block, then the buoyant force of the atmosphere is the same for both objects.
But if the balloon is just some flimsy stuff, and it lets the helium expand to a much bigger volume than the iron block, then the buoyant force on the balloon is greater than the buoyant force on the solid iron block.
In fact, it DOESN'T MATTER what's in the balloon and what's in the block. It doesn't matter whether either one of them is solid, liquid, or gas, and it doesn't matter whether they have the same or different mass.
Whichever one has greater VOLUME has a greater buoyant force of atmosphere acting on it.
We can calculate his resultant speed.
Resultant speed is:
v^2 = 5^2 + 1,9^2
v = 5,349 m/s
Now we need to find angle between resultant speed and vertical speed.
cos(alpha) = 5/5.349 = 0.9347
alpha = 20,8 degrees
Answer is 20,8 degrees
