Answer:
the last one, the third one, and the first one.
Answer:
58.5 m
Explanation:
First of all, we need to find the total time the ball takes to reach the water. This can be done by looking at the vertical motion only.
The initial vertical velocity of the ball is

where
u = 21.5 m/s is the initial speed
is the angle
Substituting,

The vertical position of the ball at time t is given by

where
h = 13.5 m is the initial heigth
is the acceleration of gravity (negative sign because it points downward)
The ball reaches the water when y = 0, so

Which gives two solutions: t = 3.27 s and t = -0.84 s. We discard the negative solution since it is meaningless.
The horizontal velocity of the ball is

And since the motion along the horizontal direction is a uniform motion, we can find the horizontal distance travelled by the ball as follows:

Answer: The observing friend will the swimmer moving at a speed of 0.25 m/s.
Explanation:
- Let <em>S</em> be the speed of the swimmer, given as 1.25 m/s
- Let
be the speed of the river's current given as 1.00 m/s.
- Note that this speed is the magnitude of the velocity which is a vector quantity.
- The direction of the swimmer is upstream.
Hence the resultant velocity is given as,
= S — S 0
= 1.25 — 1
= 0.25 m/s.
Therefore, the observing friend will see the swimmer moving at a speed of 0.25 m/s due to resistance produced by the current of the river.
Answer:
I believe the answer is B) Two wavelengths
Answer:
F = 4399 KN
Explanation:
given,
mass of automobile = 890 kg
initial speed = 48 km/h
= 48 × 0.278 = 13.34 m/s
using equation of motion
v² = u² + 2 a × s
0 = 13.34² - 2 a ×0.018

a = 4943.21 m/s²
F = m × a
F = 890 × 4943.21
F = 4399456.9 N
F = 4399 KN
hence, the Net force is F = 4399 KN