Answer:
Friction always acts opposite to the motion.
Answer:
i think it might be D or C
The mass of the aeroplane is 300,000 kg.
<h3>What is Newton's second law of motion?</h3>
It states that the force F is directly proportional to the acceleration a of the body and its mass.
The law is represented as
F =ma
where acceleration a = velocity change v / time interval t
Given is the aeroplane lands at a speed of 80 m/s. After landing, the aeroplane takes 28 s to decelerate to a speed of 10 m/s. The mean resultant force on the aeroplane as it decelerates is 750 000 N.
The force expression will be
F = mv/t
Substitute the values and we have
750000 = m x (80 -10)/ 28
750,000 = m x 2.5
m = 300,000 kg
Thus, the mass of the aeroplane is 300,000 kg.
Learn more about Newton's second law of motion.
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Answer:
U = 8.30×10-⁹J
Explanation:
m1 = m2 = 5.00kg masses of the spheres
d = 15.0cm = 15×10-²m
r = 5.10cm = 5.10×10-²m
R = d + r = 15×10-² + 5.10×10-²
R = 20.10 ×10-²m = 0.201m
G = 6.67×10-¹¹Nm²/kg²
U = Gm1×m2/R = potential energybetween the spheres
U = 6.67×10-¹¹×5.00×5.00/0.201
U = 8.30×10-⁹J
Answer:
a = - 1.987 × 10⁶ ft/s²
t = 6.84 × 10⁻⁴ s
Explanation:
v₀ = 910 ft/s
x = 5 in.
relation v = v₀ - k x
v = 0 as body comes to rest
0 = 900 - 5k/12
k = 2184 s⁻¹
acceleration

where
(A) a = -k × v
at v= 910 ft/s
a = - 1.987 × 10⁶ ft/s²
(B) at x = 3.9 in.
v = 910 - 3.9(2184)/12
v = 200.2 m/s




t = 6.84 × 10⁻⁴ s