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2 years ago

In the graph above, what is the instantaneous speed of the object after the first five seconds?

Physics

1 answer:

alexdok [17]2 years ago

8 0

Answer:

D) 25 m/s

Explanation:

In order to solve this problem we must use the following kinematics equation.

$v_{f} =v_{i} +(a*t)\\$

where:

Vf = final speed [m/s]

Vi = initial speed = 0

a = acceleration = 5[m/s^2]

t = time = 5[s]

After 5 seconds the acceleration is equal to 5 [m/s^2]

Now replacing the values in the equation:

Vf = 0 + (5*5)

Vf = 25[m/s]

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3. A model rocket takes 0.05 seconds to speed up from rest to its maximum velocity of 80 m/s.

nikklg [1K]

Answer:

$1600 \frac{m}{s^2}$

Explanation:

Acceleration is defined as the change in velocity divided by the time it took to produce such change. The formula then reads:

$a = \frac{change-in-velocity}{time} = \frac{Vf-Vi}{t}$

Where Vf is the final velocity of the object, (in our case 80 m/s)

Vi is the initial velocity of the object (in our case 0 m/s because the object was at rest)

and t is the time it took to change from the Vi to the Vf (in our case 0.05 seconds.

Therefore we have:

$a = \frac{80 m/s - 0 m/s}{0.05 sec} = 1600 \frac{m}{s^2}$

Notice that the units of acceleration in the SI system are $\frac{m}{s^2}$ (meters divided square seconds)

7 0

2 years ago

Read 2 more answers

Three cars (car F, car G, and car H) are moving with the same velocity when the driver suddenly slams on the brakes, locking the

Nastasia [14]

Answer:

Car H

Explanation:

Frictional force is a resistant force. It is given as:

F = u*m*g

Where u = coefficient of friction

m = mass

g = acceleration due to gravity

From the formula above, we see that frictional force is dependent on the mass of object and the coefficient of friction.

Since they all have the same tires, the coefficient of friction between the tire and the floor is the same for each car. Acceleration due to gravity, g, is constant.

The only factor that determines the frictional force of each car is the mass. Hence, the more the mass, the more the frictional force.

So, the most massive car will have the most frictional force and hence, will come to a stop quicker than the others. The least massive car will have the least frictional force and so, will take a longer time to stop.

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2 years ago

Why do all objects above earth's surface have gravitational potential energy

gayaneshka [121]

Gravitational potential energy is energy an object possesses because of its position in a gravitational field. The most common use of gravitational potential energy is for an object near the surface of the Earth where the gravitational acceleration can be assumed to be constant at about 9.8 m/s2.

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3 years ago

Density is a property of matter that relates

tiny-mole [99]

Density is the mass of a substance per unit volume.

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3 years ago

How does the number of valence electrons affect the reactivity?

ololo11 [35]

The less valence electrons the more reactive the element is.

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2 years ago