Answer:
they are used in periscopes,for signalling,in kaleidoscopes,to see round dangerous bends
Explanation:
Answer:
B. -38.2 m/s
Explanation:
Given parameters:
Time of fall = 4s
Unknown:
Final velocity of the rock = ?
Solution:
To solve this problem, we use the expression below;
V = U + gt
V is the final velocity
U is the initial velocity
g is the acceleration due to gravity = 9.8m/s²
t is the time taken
Now, insert the parameters and solve;
V = 0 + (9.8 x 4) = 39.2m/s
Answer:
2.83m
Explanation:
The information that we have is
Intensity at 2.0 m: and
we need an intensity level of:
thus, we are looking for the distance .
which we can find with the law for intensity and distance:
we solve for :
and we substitute the known values:
at a distance of 2.83m the intensity level is 40dB
Answer:
E. The gas absorbs 50 of energy as heat and does 50」ot work
Explanation:
This is following the law of thermodynamics that energy is neither created nor destroyed
Answer:
P.E = 1764 Joules
Explanation:
Given the following data;
Mass = 6kg
Height = 30m
We know that acceleration due to gravity is equal to 9.8m/s²
To find the potential energy;
Potential energy can be defined as an energy possessed by an object or body due to its position.
Mathematically, potential energy is given by the formula;
Where,
P.E represents potential energy measured in Joules.
m represents the mass of an object.
g represents acceleration due to gravity measured in meters per seconds square.
h represents the height measured in meters.
Substituting into the equation, we have;
P.E = 6 * 9.8 * 30
P.E = 1764 Joules