Answer:
In physics, a frame of reference, or reference frame, is a perspective that one uses to determine if an object is moving.
Explanation:
The position of the particle is given by:
x(t) = t³ - 12t² + 21t - 9
Differentiate x(t) with respect to t to find the velocity x'(t):
x'(t) = 3t² - 24t + 21
Differentiate x'(t) with respect to t to find the acceleration x''(t):
x''(t) = 6t - 24
Answer:
243 N
Explanation:
The formula for electromagnetic force is F= Kq1q2/r^2
where r is the distance between the charges, if the distance between the charges is reduced by 1/3 then F will increase by 9 [(1/3r)^2 becomes 1/9r which is 9F] so 27*9 is 243N
Answer:
Explanation:
The index of refraction is equal to the speed of light c in vacuum divided by its speed v in a substance, or 
. For our case we want to use 
, which for our values is equal to:
Which we will express with 3 significant figures (since a product or quotient must contain the same number of significant figures as the measurement with the <em>least</em> number of significant figures):
Answer:
0.15kg/m³
Explanation:
Density = mass/ volume
Given that
Mass = 150kg
Note that volume = length x breadth x height
Volume = 20 x 10 x 5
Volume = 1000m³
Density = mass ➗ volume
Density = 150kg ➗ 1000m³
Density = 0.15kg/m³
I hope this was helpful, Please mark as brainliest
