Answer:
20N
Explanation:
Ratio of N to cm-
10:2
so to make 2=4 times 2 so The ratio is now-
20:4
so to move 4 cm you need to push 20N.
Answer:

Explanation:
In an uniformly accelerated circular motion, the angle traveled by the object is given by:

Here
is the final angular speed,
is the initial angular speed and t is the time of the motion. Replacing the given values:

speed of tortoise is given as v1 = 0.14 m/s
speed of hare is given as v2 = 20*0.14 = 2.8 m/s
now let say the total length of the path is "d"
so the total time taken by the tortoise to cover this

now given that hare took rest for 1 min
so total time of run for hare is (t - 60)s
so the distance that hare covered is given by

now by above two equations



and the time t is given by


so part a)
t = 63 s
part b)
d = 8.82 m
Answer:
r₂ = 0.316 m
Explanation:
The sound level is expressed in decibels, therefore let's find the intensity for the new location
β = 10 log
let's write this expression for our case
β₁ = 10 log \frac{I_1}{I_o}
β₂ = 10 log \frac{I_2}{I_o}
β₂ -β₁ = 10 (
)
β₂ - β₁ = 10
log \frac{I_2}{I_1} =
= 3
= 10³
I₂ = 10³ I₁
having the relationship between the intensities, we can use the definition of intensity which is the power per unit area
I = P / A
P = I A
the area is of a sphere
A = 4π r²
the power of the sound does not change, so we can write it for the two points
P = I₁ A₁ = I₂ A₂
I₁ r₁² = I₂ r₂²
we substitute the ratio of intensities
I₁ r₁² = (10³ I₁ ) r₂²
r₁² = 10³ r₂²
r₂ = r₁ / √10³
we calculate
r₂ =
r₂ = 0.316 m