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3 years ago

A ball thrown straight up climbs for 3.0 sec before falling. Neglecting air resistance, with what velocity was the ball thrown?

Physics

1 answer:

sesenic [268]3 years ago

7 0

Answer:

Speed, u = 29.4 m/s

Explanation:

Given that, A ball thrown straight up climbs for 3.0 sec before falling, t = 3 s

Let u is speed with which the ball is thrown up. When the ball falls, v = 0

Using first equation of motion as :

v = u + at

Here, a = -g

So, u = g × t

$u=9.8\times 3$

u = 29.4 m/s

So, the speed with which the ball was thrown is 29.4 m/s. Hence, this is the required solution.

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Starting from rest, a basketball rolls from top of a hill to the bottom, reaching a translational speed of 6.8 m/s. Ignore frict

kkurt [141]

Answer:

Explanation:

for baseball

(a) Let the mass of the baseball is m.

radius of baseball is r.

Total kinetic energy of the baseball, T = rotational kinetic energy + translational kinetic energy

T = 0.5 Iω² + 0.5 mv²

Where, I be the moment of inertia and ω be the angular speed.

ω = v/r

T = 0.5 x 2/3 mr² x v²/r² + 0.5 mv²

T = 0.83 mv²

According to the conservation of energy, the total kinetic energy at the bottom is equal to the total potential energy at the top.

m g h = 0.83 mv²

where, h be the height of the top of the hill.

9.8 x h = 0.83 x 6.8 x 6.8

h = 3.93 m

(b) Let the velocity of juice can is v'.

moment of inertia of the juice can = 1/2mr²

So, total kinetic energy

T = 0.5 x I x ω² + 0.5 mv²

T = 0.5 x 0.5 x m x r² x v²/r² + 0.5 mv²

m g h = 0.75 mv²

9.8 x 3.93 = 0.75 v²

v = 7.2 m/s

7 0

3 years ago

What controls how fast an object falls?

Vedmedyk [2.9K]

Answer:

gravity

Explanation:

as the earth rotates on an axis, it causes an effect known as centripetal acceleration with is an acceleration that pulls objects towards the center of the object. in planets, we call this Gravity

5 0

1 year ago

Read 2 more answers

For this car, predict the shape of a graph that shows distance (x) versus time (t). Note that time is the independent variable a

Mrrafil [7]

Hope this helps!

ANSWER:

5 0

3 years ago

1. Do alto de uma plataforma com 15m de altura, é lançado horizontalmente um projéctil. Pretende-se atingir um alvo localizado n

sveta [45]

Answer:

(a). The initial velocity is 28.58m/s

(b). The speed when touching the ground is 33.3m/s.

Explanation:

The equations governing the position of the projectile are

$(1).\: x =v_0t$

$(2).\: y= 15m-\dfrac{1}{2}gt^2$

where $v_0$ is the initial velocity.

(a).

When the projectile hits the 50m mark, $y=0$ ; therefore,

$0=15-\dfrac{1}{2}gt^2$

solving for $t$ we get:

$t= 1.75s.$

Thus, the projectile must hit the 50m mark in 1.75s, and this condition demands from equation (1) that

$50m = v_0(1.75s)$

which gives

$\boxed{v_0 = 28.58m/s.}$

(b).

The horizontal velocity remains unchanged just before the projectile touches the ground because gravity acts only along the vertical direction; therefore,

$v_x = 28.58m/s.$