A car is traveling at 100 km/h when the driver sees an accident 80 m ahead and slams on the brakes. what minimum constant decele
1 answer:
Assuming the driver starts slamming the brakes immediately, the car moves by uniformly decelerated motion, so we can use the following relationship
(1)
where
a is the deleceration
S is the distance covered after a time t
is the velocity at time t
is the initial speed of the car
The accident is 80 m ahead of the car, so the minimum deceleration required to avoid the accident is the value of a such that S=80 m and
(the car should stop exactly at S=80 m to avoid the accident). Using these data, we can solve the equation (1) to find a:
And the negative sign means it is a deceleration.
where
a is the deleceration
S is the distance covered after a time t
The accident is 80 m ahead of the car, so the minimum deceleration required to avoid the accident is the value of a such that S=80 m and
And the negative sign means it is a deceleration.
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Answer:
D/H =15
Explanation:
- We can find first the peak height H, taking into consideration, that at the maximum height, the ball will reach momentarily to a stop.
- At this point, we can find the value of H, applying the following kinematic equation:
- If vf=0, if we assume that the positive direction is upwards, we can find the value of H as follows:
- We can use the same equation, to find the value of D, as follows:
- In order to find v₁, we can use the same kinematic equation that we used to get H, but now, we know that v₀ = 0.
- When we replace these values in (1), we find that v₁ = -v₀.
- Replacing in (3), we have:
- Solving for D:
- From (2) we know that H can be expressed as follows:
- ⇒ D = 15 * H
Answer:
The maximum energy that can be stored in the capacitor is 6.62 x 10⁻⁵ J
Explanation:
Given that,
dielectric constant k = 5.5
the area of each plate, A = 0.034 m²
separating distance, d = 2.0 mm = 2 x 10⁻³ m
magnitude of the electric field = 200 kN/C
Capacitance of the capacitor is calculated as follows;
Maximum potential difference:
V = E x d
V = 200000 x 2 x 10⁻³ = 400 V
Maximum energy that can be stored in the capacitor:
E = ¹/₂CV²
E = ¹/₂ x 8.275 x 10⁻¹⁰ x (400)²
E = 6.62 x 10⁻⁵ J
Therefore, the maximum energy that can be stored in the capacitor is 6.62 x 10⁻⁵ J
An advertisement for an all-terrain vehicle (ATV) claims that the ATV can climb inclined slopes of 35°. The minimum coefficient of static friction needed for this claim to be possible is 0.7
In an inclined plane, the coefficient of static friction is the angle at which an object slide over another.
As the angle rises, the gravitational force component surpasses the static friction force, as such, the object begins to slide.
Using the Newton second law;
- So; On the L.H.S
- On the R.H.S
N = mg cos θ
Equating both force component together, we have:
From trigonometry rule:
∴
Therefore, we can conclude that the minimum coefficient of static friction needed for this claim to be possible is 0.7
Learn more about static friction here:
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