First, we need to convert the units of the given velocity to m/sec
144 km/hr = (144 km / hr) x (1000 m / 1 km) x (1 hr / 3600 s) = 40 m/s
Now, to solve this question, we can use one of the equations of motion:
a = (Vf - Vi) / t where:
a is the acceleration we are looking for
Vf is the final velocity of the car = 0 m/sec
Vi is the initial velocity of the car = 40 m/sec
t is the time taken = 12 seconds
Substitute with these givens in the above equation to get the acceleration as follows:
a = (0-40)/12 = -3.334 m/s^2
Answer:
C. Tag the hummingbirds with transmitters and track their movement.
Explanation:
Hypothesis refers to the conclusion of the analysis found on the grounds of certain observations. The hypothesis is further tested and verified by performing certain experiments. In the given excerpt, Juan hypothesizes that certain group of hummingbirds fly to certain locations depending upon the season. To test the hypothesis, Juan can experiment with finding and tracking the hummingbirds and the direction in which they fly. Tagging the hummingbirds with transmitters and tracking their movement would help Juan concluding about the hypothesis.
With an acceleration of 4.0 m/s², the bottle attains a speed of
(4.0 m/s²) * (9.0 s) = 36 m/s
so that the slide has length ∆<em>x</em> such that
(36 m/s)² - 0² = 2 * (4.0 m/s²) * ∆<em>x</em>
==> ∆<em>x</em> = 162 m ≈ 160 m
Alternatively, we know the bottle covers a distance ∆<em>x</em> with acceleration <em>a</em> at time <em>t</em> according to
∆<em>x</em> = 1/2 <em>a</em> <em>t</em>²
so that
∆<em>x</em> = 1/2 * (4.0 m/s²) * (9.0 s)² = 162 m ≈ 160 m
The resultant force will be equal to difference of her downward force, her weight, and the upward force, the air resistance.
Fnet = 657 - 51.1 x 9.81
= 149.7 N
F = ma
a = F / m
a = 149.7/51.1
a = 2.93 m/s²
