Lower resistivity means higher conductivity: among these materials, the best conductor is silver, therefore it must be the material with lowest resistivity among those. We can also have a look at the value of resistivity of the different materials listed in the problem, to check our answer. The resistivities of the materials are the following:
Wood:

Salt water:

Silver:

Lead:

<span>We see that the material with lowest resistivity among those is silver, therefore the correct answer is silver.</span>
Answer:
the range or the ball is 48.81 m
Explanation:
given;
Nicole throws a ball at 25 m/s at an angle of 60 degrees abound the horizontal.
find:
What is the range of the ball?
solution:
let Ф = 25°
Vo = 25 m/s
<u>consider x-motion using time of fight: x = Vox * t</u>
where x = R = range
t =<u> 2 Voy </u>
g
R =<u> Vo² sin (2Ф)</u>
g
plugin values into the formula:
R = <u>(25)² sin (2*25) </u>
9.81
R = 48.81 m
therefore, the range or the ball is 48.81 m
Answer:

Explanation:
Assume that the distance travelled initially is d.
In order to stop the block you need some external force which is friction.
If we use the law of energy conservation:

a)
Looking at the formula you can see that the mass doesn't affect the distance travelled, as lng as the initial velocity is constant (Which indicates that the force must be higher to push the block to the same speed) therefore the distance is the same.
b) If the velocity is doubled, then the distance travelled is multiplied by 4, because the distance deppends on the square of the velocity.
The reason why a delivery truck filled with birds sitting on the floor be heavier than a truck with the same birds flying around is because when the birds are sitting on the floor, they are adding their weight to the truck.
Meanwhile, if the birds are flying around they aren't resting on the truck or touching it, so therefore their weight wouldn't be added to the truck.
The mass of the truck will remain the same as you cannot change the mass but the weight will vary depending on the items and objects placed in it.
To solve this problem we will apply the concept related to the kinetic energy theorem. Said theorem states that the work done by the net force (sum of all forces) applied to a particle is equal to the change experienced by the kinetic energy of that particle. This is:


Here,
m = mass
v = Velocity
Our values are given as,


Replacing,


Therefore the mechanical energy lost due to friction acting on the runner is 907J