Answer:
(2) The excess negative charge from the sphere spread out all over your body.
(7) After you touched it, the metal sphere was very nearly neutral.
Explanation:
Plastic pen repels magic tape so magic tape is also negatively charged . Further , magic tape repels small metal sphere that means small sphere also is negatively charged.
Now when small sphere is touched by a man insulated from ground , the charge is distributed between man and small sphere according to their capacitance .
Since human body will have greater capacitance ,it will acquire larger share of charge . Sphere being of very small size will retain very less charge and it will become almost neutral . Hence it will be attracted by charged tape .
Answer:
The height of the bridge is 78.4 m.
Explanation:
Given;
time of the stone motion off the bridge, t = 4.0 s
acceleration due to gravity, g = 9.8 m/s²
The height of the bridge is given by;
h = ut + ¹/₂gt²
where;
u is the initial velocity of the stone, u = 0
h = ¹/₂gt²
h = ¹/₂(9.8)(4)²
h = 78.4 m
Therefore, the height of the bridge is 78.4 m.
Answer:
<h2>17.1 N</h2>
Explanation:
The force acting on an object given it's mass and acceleration can be found by using the formula
force = mass × acceleration
From the question
3800 g = 3.8 kg
We have
force = 3.8 × 4.5
We have the final answer as
<h3>17.1 N</h3>
Hope this helps you
Answer:
The correct answer is a) The kinetic energy of the ice increases by equal amounts for equal distances.
Explanation:
The law of conservation states that the energy cannot be created nor be destroyed but can be converted from one form to another.Before the ice even starts falling we already know that it possesses energy in the form of potential energy given by P=mgh where m is the mass of the ice , g is the acceleration due to gravity and h is the height of the ice above the ground whatever that may be, since a number is not given here.As the ice falls the energy is converted from potential energy to kinetic energy. We notice one thing about the equation for the potential energy P , which is that it is not only directly proportional to h but also is linear in h as well(which is the main reason why a) is correct) which means that if the ice drops by 1 meter the potential energy it will have lost would be ΔPE=mgΔh=-mg, where Δh is the change in its height which is 1 meter here.And according to the principle of conservation of energy this energy must be converted to kinetic energy so the ΔKE=-ΔPE=mg, and this process repeats and for each meter it falls, it picks up the same amount of kinetic energy equaling mg(which is the same as the loss in PE per each meter of fall). So a 2 meter decrease in height will result in an increase in KE of 2mg, a 3 meter decrease in height will result in an increase in KE of 3mg. gain in kinetic energy only depends on the drop in height, which is true irrespective of where the ice might happen to be in its journey close to the top or the bottom. So the drop in height of lets say x at any point in the journey will result in the same increase in KE = ΔKE = mgx. Which proves part a) to be correct.
Thermal energy from the coffee is transferred to the mug.
