Answer:
640 m.
Explanation:
The following data were obtained from the question:
Acceleration (a) = –20 m/s/s
Time (t) = 8 s
Final velocity (v) = 0 m/s
Distance (s) =.?
Next, we shall determine the initial velocity (u) of the car. This can be obtained as follow:
Acceleration (a) = –20 m/s/s
Time (t) = 8 s
Final velocity (v) = 0 m/s
Initial velocity (u)
a = (v – u) / t
–20 = (0 – u) / 8
–20 = – u / 8
Cross multiply
–20 × 8 = – u
– 160 = – u
Divide both side by – 1
u = – 160 / – 1
u = 160 m/s
Finally, we shall determine the distance travelled by the car before stopping as follow:
Time (t) = 8 s
Final velocity (v) = 0 m/s
Initial velocity (u) = 160 m/s
Distance (s) =.?
s = (v + u)t /2
s = (0 + 160) × 8 /2
s = (160 × 8) /2
s = 1280 / 2
s = 640 m
Therefore, the car travelled 640 m before stopping.
Answer:
1) v = 7.70 10³ m/s
, 2) F = 115 N and 3) (F/W)% = 90.2%
Explanation:
1) To solve the problem let's use Newton's second law where force is gravitational force and acceleration is centripetal
F = ma.
F = G m M / r²
a = v² / r
G m M / r² = m v² / r
G M / r = v²
Let's look for the distance is the distance from the surface of the has to the station 345 103 m plus the radius of the Earth
r = Re + 345 103
r = 6.37 10⁶ + 3.45 10⁵
r = 6.715 10⁶ m
Let's calculate the speed
v = √ (6.67 10⁻¹¹ 5.98 10²⁴ / 6,715 10⁶) = √ (59,399 10⁶)
v = 7.70 10³ m/s
The speed module is constant, so we can use the uniform motion relationships
v = d / t
The distance is the length of the circle
d = 2π r
d = 2π 6.715 106
d = 42.2 10⁶ m
Let's calculate the time
t = d / v
t = 42.2 10⁶ / 7.70 10³
t = 5.48 10³ s
2) Let's use the universal gravitation equation
F = G m M / r²
F = 6.67 10⁻¹¹ 13.0 5.98 10²⁴ /(6.715 10⁶)²
F = 11.5 10¹ N
F = 115 N
3) in this for we are asked the relationship is out with the weight of the body on earth
F / W = F / mg
F / W = 115 / (13.0 9.8)
F / W = 0.902
F / W% = 90.2%
A 60.0 kg secretary running up a 4.0 m tall flight of stairs in 4.2 s has an average power of 560 W (Option b).
<h3>What is power?</h3>
Power is the work done over a period of time.
A secretary with a mass (m) of 60.0 kg runs up a 4.0 m (d) tall flight of stairs. Given gravity (g) is 9.81 m/s², the work (W) done is:
W = m × g × d = 60.0 kg × 9.81 m/s² × 4.0 m = 2.35 × 10³ J
They do 2.4 × 10³ J of work in 4.2 s (t). The average power (P) is:
P = W / t = 2.35 × 10³ J / 4.2 s = 560 W
A 60.0 kg secretary running up a 4.0 m tall flight of stairs in 4.2 s has an average power of 560 W (Option b).
Learn more about power here: brainly.com/question/911620
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