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ale4655 [162]
3 years ago
10

If a ball with an original velocity of 0 is dropped from a tall structure and takes 7 Seconds to hit the ground what velocity do

es the ball have when it reaches the ground
A. 156.8

B. 240.1

C. 68.6

D. 34.3
Physics
1 answer:
MrMuchimi3 years ago
5 0

Gravity adds 9.8 m/s to the downward speed of a falling object every second. (On Earth.)

In 7 seconds, gravity adds (7 x 9.8 m/s) = <em>68.6 m/s</em> to the downward speed of a falling object.

(IF air resistance has no effect on the object.)

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ListenA person on a ledge throws a ball vertically downward, striking the ground below the ledge with 200 joules of kinetic ener
polet [3.4K]

Answer:

A. 200 J

Explanation:

The initial kinetic energy depends on the initial speed, while the gravitational potential energy depends on the height, both balls are thrown with the same initial speed and from the same height. Therefore, due to the law of conservation of energy, the balls must have the same mechanical energy (the sum of both energies) when both impact the ground. Since the potential energy is zero at this point, its final kinetic energy must also be the same.

8 0
3 years ago
Find the speed required to throw a ball straight up and it return 6 seconds later. Neglect air resistance
Nadya [2.5K]

Answer:

the ball will go up 3s and down 3s

v=gt

where t=3s and g=9.8m/s^2

distance=v0(t)+(1/2)gt^2

where initial velocity (v0)=0

Explanation:

8 0
3 years ago
Master of physics needed
Delicious77 [7]
Hey JayDilla, I get 1/3.  Here's how:
Kinetic energy due to linear motion is:
E_{linear}= \frac{1}{2}mv^2
where
v=r \omega
giving
E_{linear}= \frac{1}{2}mr^2 \omega ^2

The rotational part requires the moment of inertia of a solid cylinder
I_{cyl} =  \frac{1}{2}mr^2
Then the rotational kinetic energy is
E_{rot}= \frac{1}{2}I \omega ^2= \frac{1}{4}mr^2 \omega ^2
Adding the two types of energy and factoring out common terms gives
\frac{1}{2}mr^2 \omega ^2(1+ \frac{1}{2})
Here the "1" in the parenthesis is due to linear motion and the "1/2" is due to the rotational part.  Since this gives a total of 3/2 altogether, and the rotational part is due to a third of this (1/2), I say it's 1/3.

8 0
4 years ago
How much work is done by an applied force to lift a 45 newton block 6.0 meters at a constant speed ?
AleksandrR [38]

Answer:

270Joues

Explanation:

Step one:

given data

Force F= 45N

distance moved d= 6m

Required

The work done in moving the block 6m

Step two:

We know that the expression for the work done is

WD= force* distance

WD= 45*6

WD=270Joues

7 0
3 years ago
You are given a copper bar of dimensions 3 cm × 5 cm × 8 cm and asked to attach leads to it in order to make a resistor. If you
max2010maxim [7]

Answer:

c. 5cm \times 8cm

Explanation:

The dimensions 5cm\times 8cm have the highest cross-sectional area combination of 40cm^2.

-Resistance reduces with an increase in cross sectional area.

-Reason-Electrons have alarger area to flow through.

8 0
4 years ago
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