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3 years ago

In the video, forces acting on the car that are parallel to the direction of motion are analyzed. how are these forces related?

1 answer:

5 0

The drag force acts opposite to the direction the cars' motion and the propelling force is in the direction of the motion. These are the two forces acting on the car and since they are both equal and opposite in direction, they cancel out each other. Thus, the car is able to move at a constant speed without changing its direction or momentum.

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Running with an initial velocity of +11m/s, a horse has an average acceleration of -1.81m/s 2 . How long does it take for the ho

Ronch [10]

Answer:

2.49 seconds

Explanation:

From the question,

a = (v-u)/t............................ Equation 1

Where a = acceleration, v = final velocity, u = initial velocity, t = time

Make t the subject of the equation

t = (v-u)/a.......................... Equation 2

Given: v = 6.5 m/s, u = 11 m/s, a = -1.81 m/s²

Substitute these values into equation 2

t = (6.5-11)/(-1.81)

t = -4.5/-1.81

t = 2.49 s

6 0

3 years ago

If a car rolls gently off a vertical cliff, how long does it take to reach 90km/hr.

Naddik [55]

90 km/h : 3.6 = 25 m/s. If you know that on earth g = 9.81 m/s^2, then all you have to do is divide the speed by g. 25/9.81 = 2.548 seconds

At least, if by 'gently rolls off a vertical cliff' means that your starting velocity equals zero.

5 0

3 years ago

Select the correct answer. Five marbles roll down a ramp. Each marble reaches the bottom of the ramp at a speed of 3 meters/seco

MA_775_DIABLO [31]

Kinetic energy = (1/2) * mass * velocity

Marble 1 = (1/2) * 10 * 3 = 15 Joules

Marble 2 = 30 J

Marble 3 = 37.5 J

Marble 4 = 60 J

Marble 5 = 45 J

Marble 4 has the most kinetic energy - D.

4 0

3 years ago

Read 2 more answers

The L-ft ladder has a uniform weight of W lb and rests against the smooth wall at B. θ = 60. If the coefficient of static fricti

Colt1911 [192]

This question is incomplete, the complete question;

The L-ft ladder has a uniform weight of W lb and rests against the smooth wall at B. θ = 60. If the coefficient of static friction at A is μ = 0.4.

Determine the magnitude of force at point A and determine if the ladder will slip. given the following; L = 10 FT, W = 76 lb

Answer:

- the magnitude of force at point A is 79.1033 lb

- since FA < FA_max; Ladder WILL NOT slip

Explanation:

Given that;

∑'MA = 0

⇒ NB [Lsin∅] - W[L/2.cos∅] = 0

NB = W / 2tan∅ -------let this be equation 1

∑Fx = 0

⇒ FA - NB = 0

FA = NB

therefore from equation 1

FA = NB = W / 2tan∅

we substitute in our values

FA = NB = 76 / 2tan(60°) = 21.9393 lb

Now ∑Fy = 0

NA - W = 0

NA = W = 76 lb

Net force at A will be

FA' = √( NA² + FA²)

= √( (W)² + (W / 2tan∅)²)

we substitute in our values

FA' = √( (76)² + (21.9393)²)

= √( 5776 + 481.3328)

= √ 6257.3328

FA' = 79.1033 lb

Therefore the magnitude of force at point A is 79.1033 lb

Now maximum possible frictional force at A

FA_max = μ × NA

so, FA_max = 0.4 × 76

FA_max = 30.4 lb

So by comparing, we can easily see that the actual friction force required for keeping the the ladder stationary i.e (FA) is less than the maximum possible friction available at point A.

Therefore since FA < FA_max; Ladder WILL NOT slip

5 0

3 years ago

You are one of the forensic anthropologist working on the Romanov Family investigation. You and your team are trying to determin

yawa3891 [41]

Answer:

Femur

Explanation:

The bone to forensically analyze in order to create a height profile of the victims would the femur.

The approximate height of a human can best be estimated by measuring the length of the bone that runs from the hip to the knee, otherwise known as the femur.

For the males, the length of the femur in centimeters is multiplied by 2.32 followed by the addition of 65.53 in order to arrive at the approximate height of the individual. For the females, on the other hand, the length of the femur in centimeters is multiplied by 2.47 followed by the addition of 54.1.

7 0

3 years ago