All categories

4 years ago

Some help please physics

Physics

2 answers:

salantis [7]4 years ago

3 0

My best guess is A There is missing a time unit in the question. I know that 4.4 *5 = 21 so that would be my best guess.

REY [17]4 years ago

3 0

The car's AVERAGE speed is (21/2)=10.5 m/s. (Zero at the beginning, 21 at the end.). In order to cover 50m at an average speed of 10.5 m/s, it takes (50/10.5)=4.76 seconds. It took 4.76 seconds to accelerate to 21 m/s^2, so the average acceleration is (21/4.76)=4.2 seconds. You probably had a formula in class that would take you to 4.4, but this is the way I think it through without a lot of formulas.

You might be interested in

A material through which electricity cannot flow is called:

Julli [10]

Answer:

el conductor

Explanation:

gracias por los puntitoss

7 0

3 years ago

The diameters of bolts produced by a certain machine are normally distributed with a mean of 0.30 inches and a standard deviatio

enot [183]

Answer:

2.25 %

Explanation:

65-95-99.7 is a rule to remember the precentages that lies around the mean.

at the range of mean ( $\mu$ ) plus or minus one standard deviation ( $\sigma$ ), $P([\mu-\sigma \leq X \leq \mu+\sigma])\approx 68.3%$

at the range of mean plus or minus two standard deviation, $P([\mu -2\sigma \leq X \leq \mu+2\sigma])\approx 95.5%$

at the range of mean plus or minus three standard deviation, $P([\mu - 3\sigma\leq X \leq \mu+3\sigma])\approx 99.7%$

So, note that they are asking about the probability that it is greater than 0.32, that is the mean (0.3) plus two times the standard deviation (0.1) ( $P(X \leq \mu+2\sigma)$ )

So we know that the 95.5% is between $\mu - 2\sigma = 0.3 -2*0.1 = 0.28$ and $\mu + 2\sigma = 0.3 +2*0.1 = 0.32$ , hence approximately the 4.5% (100%-95.5%) is greater than 0.32 or less than 0.28. But half (4.5%/2=2.25%) is greater than 0.32 and the other half is less than 0.28.

So $P(X \leq \mu+2\sigma) \approx 2.25%$

8 0

3 years ago

You exert 375 J to move a 45-kg object 5 m. How much force is required?

Serjik [45]

The amount of force required is 69J

8 0

3 years ago

What is the difference between a psychologist and a psychiatrist?

vfiekz [6]

Answer:

Psychiatrists are medical doctors, psychologists are not. Psychiatrists prescribe medication, psychologists can't. Psychiatrists diagnose illness, manage treatment and provide a range of therapies for complex and serious mental illness. Psychologists focus on providing psychotherapy (talk therapy) to help patients.

Explanation:

5 0

3 years ago

Read 2 more answers

A 4.00-m long rod is hinged at one end. The rod is initially held in the horizontal position, and then released as the free end

Natalka [10]

Answer:

The angular acceleration α = 14.7 rad/s²

Explanation:

The torque on the rod τ = Iα where I = moment of inertia of rod = mL²/12 where m =mass of rod and L = length of rod = 4.00 m. α = angular acceleration of rod

Also, τ = Wr where W = weight of rod = mg and r = center of mass of rod = L/2.

So Iα = Wr

Substituting the value of the variables, we have

mL²α/12 = mgL/2

Simplifying by dividing through by mL, we have

mL²α/12mL = mgL/2mL

Lα/12 = g/2

multiplying both sides by 12, we have

Lα/12 × 12 = g/2 × 12

αL = 6g

α = 6g/L

α = 6 × 9.8 m/s² ÷ 4.00 m

α = 58.8 m/s² ÷ 4.00 m

α = 14.7 rad/s²

So, the angular acceleration α = 14.7 rad/s²

5 0

3 years ago