All categories

3 years ago

Which describes an object in projectile motion? Select three options.

Physics

2 answers:

Karo-lina-s [1.5K]3 years ago

8 0

Description of an object in projectile motion is;

Gravity acts to pull the object down.
The object’s inertia carries it forward.
The path of the object is curved.

Explanation:

The path of the projectile is usually curved, and NOT straight, due to the influence of gravity on it which is teh only force acting on it-, causing it motion path to fall towards the earth. Most projectiles follow a parabolic path. The projectile, even though it was launched, its motion is then only due to its own inertia – tendency to stay in motion in a straight line, or rest, unless an external force is acting on it - such as drag or friction. An example of such projectile motion is of ballistic missiles.

morpeh [17]3 years ago

7 0

Answer:

it is 1,4, and 5 on edg

Explanation:

You might be interested in

I would like help with this physics problem

Darina [25.2K]

(a) This is a freefall problem in disguise - when the ball returns to its original position, it will be going at the same speed but in the opposite direction. So the ball's final velocity is the negative of its initial velocity.

Recall that

$v_f=v_i+at$

We have $v_f=-v_i$ , so that

$-2v_i=at\implies-2\left(8\,\dfrac{\mathrm m}{\mathrm s}\right)=\left(-2\,\dfrac{\mathrm m}{\mathrm s^2}\right)t\implies t=8\,\mathrm s$

(b) The speed of the ball at the start and at the end of the roll are the same 8 m/s, so the average speed is also 8 m/s.

(d) The position of the ball $x_f$ at time $t$ is given by

$x_f=x_i+v_it+\dfrac12at^2$

Take the starting position to be the origin, $x_i=0$ . Then after 6 seconds,

$x_f=\left(8\,\dfrac{\mathrm m}{\mathrm s}\right)(6\,\mathrm s)+\dfrac12\left(-2\,\dfrac{\mathrm m}{\mathrm s^2}\right)(6\,\mathrm s)^2=42\,\mathrm m$

so the ball is 42 m away from where it started.

We're not asked to say in which direction it's moving at this point, but just out of curiosity we can determine that too:

$x_f-x_i=\dfrac{v_i+v_f}2t\implies42\,\mathrm m=\dfrac{8\,\frac{\mathrm m}{\mathrm s}+v_f}2(6\,\mathrm s)\implies v_f=6\,\dfrac{\mathrm m}{\mathrm s}$

Since the velocity is positive, the ball is still moving up the incline.

8 0

2 years ago

DochEvi [55]

Answer:

Explanation:

A novae in astronomy means an explosion in the white dwarf star which had tapped enough gas from a companion star,hence it releases an incredible amount of energy which is Over a million times brighter than it normal stars.

A super novae on the other hand is a cosmic explosion that can be a billion times brighter than the normal.

From this one can see that a perculiar similarity between a novae and super novae is that both generate huge explosion and bright Ness, and a major difference is super novae release huge amount of brightness and energy more than the novae

3 0

2 years ago

A projectile is fired with an initial speed of 40 m/s at an angle of elevation of 30∘. Find the following: (Assume air resistanc

BabaBlast [244]

Answer:

a. 2.0secs

b. 20.4m

c. 4.0secs

d. 141.2m

e. 40m/s, ∅= -30°

Explanation:

The following Data are giving

Initial speed U=40m/s

angle of elevation,∅=30°

a. the expression for the time to attain the maximum height is expressed as

$t=\frac{usin\alpha }{g}$

where g is the acceleration due to gravity, and the value is 9.81m/s if we substitute values we arrive at

$t=40sin30/9.81\\t=2.0secs$

b. the expression for the maximum height is expressed as

$H=\frac{u^{2}sin^{2}\alpha }{2g} \\H=\frac{40^{2}0.25 }{2*9.81} \\H=20.4m$

c. The time to hit the ground is the total time of flight which is twice the time to reach the maximum height ,

Hence T=2t

T=2*2.0

T=4.0secs

d. The range of the projectile is expressed as

$R=\frac{U^{2}sin2\alpha}{g}\\R=\frac{40^{2}sin60}{9.81}\\R=141.2m$

e. The landing speed is the same as the initial projected speed but in opposite direction

Hence the landing speed is 40m/s at angle of -30°

3 0

2 years ago

What constant acceleration in si units must a car have to go from zero to 60 mph in 10s. what fraction of g is this?

Sophie [7]

The acceleration of the car in SI units is 2.68m/s².

The acceleration is 0.27 times the acceleration due to gravity g.

Convert the speed in mph into m/s.

1 mile = 1609 m and 1h = 3600 s.

Therefore,

$v=(\frac{60 miles}{1 h} )(\frac{1609 m}{1 mile} )(\frac{1h}{3600s)} =26.82m/s$

Acceleration is the rate of change of velocity. The car starts from rest , its initial velocity u = 0 and accelerates to a velocity v of 26.82 m/s in 10 s.

Use these values in the equation and calculate the acceleration.

$a=\frac{v-u}{t} \\ =\frac{(26.82 m/s)-(0m/s)}{10s} \\ =2.682 m/s^2$

Thus the car accelerates at a rate of 2.68 m/s².

The acceleration due to gravity g on Earth has a value 9.81 m/s².

Find the ratio $\frac{a}{g}$

$\frac{a}{g} =\frac{2.682m/s^2}{9.81m/s^2} \\ =0.27
a=0.27g$

The car's acceleration is 0.27 times the value of g.

3 0

2 years ago

A fancart of mass 0.8 kg initially has a velocity of < 0.9, 0, 0 > m/s. Then the fan is turned on, and the air exerts a co

Dmitry [639]

Answer:

<-0.45, 0, 0> kgm/s

Explanation:

The change in momentum would equal to the impulse generated by force F = <-0.3, 0, 0> over time duration of Δt = 1.5 second. The impulse is defined as the product of force F and the duration Δt

$\Delta p = F \Delta t = (-0.3) * 1.5 = -0.45 kgm/s$

So the change in momentum is <-0.45, 0, 0> kgm/s

6 0

2 years ago