Answer:
<em>The skydiver needs 0.71 seconds to reach 7 m/s</em>
Explanation:
<u>Free Fall Motion
</u>
When an object is dropped in free air (no friction) from a certain height h, it follows a free-fall motion, whose acceleration is due exclusively to gravity. The speed at a moment t when the object is dropped (from rest) is:
We need to find How long does the skydiver needs to reach 7 m/s. We solve for t
The skydiver needs 0.71 seconds to reach 7 m/s
spray him in the eyes and you have until he washes it put
Answer:
Protecting the Seashore
Seashore Conservation Code
When investigating a seashore it is important to remember that the welfare of the plants and animals must come first. If seaweeds are attached to rocks do not try to pull them off, just examine them where they are growing. Handle animals with great care, returning them to the place where they were found. Anemones and limpets are normally firmly stuck to rocks and any attempt to remove them may result in their death. Replace any large stones that are removed – animals that live on the underside soon die if left exposed.
Pollution Problems
Seas and seashores are under continual threat from pollution. Here are some examples:-
oil rigOil spills, either accidental or deliberate, have a devastating effect on marine life, especially seabirds. Black tar-like oil washed up on a rocky shore would obviously completely destroy the entire community of living things. Chemicals used to disperse oil spills on a shore may effectively clean up the oil, but they can also cleanse the shore of life! The best policy for marine life is to physically remove as much oil as possible and leave the rest to degrade naturally. A rocky shore will recover much more quickly if chemicals are not used.
Sewage and litter also upsets seashore ecosystem, making them unsightly and perhaps contaminated. Some litter can be dangerous to wildlife.
Toxic chemicals and radioactive waste - a cocktail of toxic chemicals have found their way into the sea over the years, affecting both marine and human life. For many years potentially deadly radioactive waste from nuclear power stations and other sources was disposed of in the sea, and beaches have been contaminated by accidental leakages from nuclear power stations.
Explanation:
A 59 kg sprinter, starting from rest, runs 47 m in 7.0 s at constant acceleration.?
What is the sprinter's power output at 2.0 s, 4.0 s, and 6.0 s?
Instantaneous Power is the force times velocity
P = Fv
Because the acceleration is constant, the force will be constant as well
F = ma
P = mav
for constant acceleration, the velocity at each time is found using
v = at
P = ma(at) = ma²t
find the acceleration using kinematic equation
s = ½at²
a = 2s/t²
a = 2(47) / 7.0²
a = 1.918 m/s²
P(2.0) = 59(1.918²)2.0 = 434.25 W = 0.43 kW
P(4.0) = 59(1.918²)4.0 = 868.51 W = 0.87 kW
P(6.0) = 59(1.918²)6.0 = 1302.76 W = 1.3 kW
I hope this helped.
