The question involves the knowledge of kinematics and dynamics. The answers are;
a) Time taken to stop the car = 10 s
b) The operation that slows the car is Friction
c) The size of the force = 1200 N
<h3>
What is Deceleration ?</h3>
Deceleration is the opposite of acceleration. When an object is going to rest, it will be decelerating and the final velocity will be equal to zero.
Given that the driver of a car moving at 15 m/s along a straight level road applies the brakes. The car decelerates at a steady rate of 3/2 m/s²
a) How long does the car take to stop can be found by using the formula
v = u - at
Where
Substitute all the parameters into the formula
0 = 15 - 1.5t
1.5t = 15
t = 15/1.5
t = 10 s
b) The description of the operation that slows the car down after the brake pedal is pressed is simply friction.
c) If the mass of the car is 800. The size of the force slowing the car down will be F = ma
F = 800 × 1.5
F = 1200 N
Therefore, the time taken to stop the car is 10 s and the force slowing the car down is 1200 N
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And return to their normal position after the wave passes.
Answer:
The answer is "Choice C ".
Explanation:
The relationship between the E and V can be defined as follows:
Let,
When E=0
v is a constant value
Therefore, In the electric potential in a region is a constant value then the electric-field must be into zero that is everywhere in the given region, that's why in this question the "choice c" is correct.
Answer:
The angular speed (in rev/s) when her arms and one leg open outward is 1.161 rev/s
Explanation:
Given;
moment of inertia of a skater with arms out, = 3.1 kg.m²
moment of inertia of a skater with arms in, = 0.9 kg.m²
inward angular speed, = 4 rev/s
The angular momentum of the skater when her arms are out and one leg extended is equal to her angular momentum when her arms and legs are in.
Therefore, the angular speed (in rev/s) when her arms and one leg open outward is 1.161 rev/s
Let v = the launch velocity.
Because the launch angle is 40° (with the horizontal), the initial vertical velocity is
v* sin(40°) = 0.6428v m/s.
Assume g = 9.8 m/s² and ignore air resistance.
At maximum height, the vertical velocity is zero.
Because the maximum vertical height is 10 m, therefore
(0.6428v m/s)² - 2*(9.8 m/s²)(10 m) = 0
0.4132v² = 196
v = 21.78 m/s
Answer: 21.8 m/s (nearest tenth)