If the current takes him downstream we must find the resultant vector of the velocities:

Then if the river is 3000 m-wide the swimmer will have to pass:
1.3520747 · 300 = 4056.14 m t = 4056.14 m : 1 m/s
a ) It takes
4056.15 seconds ( 1 hour 7 minutes and 36 seconds ) to cross the river.
b ) 0.91 · 3000 =
2730 mHe will be 2730 m downstream.
Answer:
C.) Gravity
Explanation:
The projectile is an object upon which the only force is gravity. Gravity acts to influence the vertical motion of the projectile.
Answer:
B. d(low)=4d(high)
Explanation:
Frequency of a string can be written as;
f = v/2L
Where;
v = sound velocity
L = string length
Frequency can be further expanded to;
f = v/2L = (1/2L)√(T/u) ......1
Where;
m= mass,
u = linear density of string,
T = tension
p = density of string material
A = cross sectional area of string
d = string diameter
u = m/L .......2
m = pAL = p(πd^2)L/4 (since Area = (πd^2)/4)
f = (1/2L)√(T/u) = (1/2L)√(T/(m/L))
f = (1/2L)√(T/((p(πd^2)L/4)/L))
f = (1/2L)√(4T/pπd^2)
f = (1/L)(1/d)√(4T/pπ)
Since the length of the strings are the same, the frequency is inversely proportional to the string diameter.
f ~ 1/d
So, if
4f(low) = f(high)
Then,
d(low) = 4d(high)
Answer:
Change in mechanical energy = work done by friction
so it is equal to

Explanation:
As we know that change in mechanical energy must be equal to the work done by non conservative forces only
So here when block moves down the inclined plane then the work done by friction force is given as

here we have

here we know that

so we have


Now the friction force on the block is given as



now work done by the friction is given as


Yes yes it will............