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Anvisha [2.4K]
3 years ago
14

A ball is thrown straight up with an initial speed of 30 m/s. How long will it take to reach the top of its trajectory, and high

will the ball go?
Physics
1 answer:
stiv31 [10]3 years ago
8 0

Answer:

About 3.06 seconds

Explanation:

v_f=v_o+at

Since at the peak of its trajectory, the ball will have no velocity, you can write the following equation:

0=30+(-9.81)t\\\\-30=-9.81t\\\\t\approx 3.06s

Hope this helps!

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About how much time elapses between high tides on the same day?
Pani-rosa [81]
There is about 12 hours
6 0
3 years ago
A see-saw is balanced on a pivot with two children on it. One child is sitting 1.5 m to the left of the pivot and has a mass of
Lorico [155]

Answer:

Explanation:

Remark

This is a second class lever. It is much more efficient than the fishing pole problem. All distances are measured from the pivot in these kinds of questions.

Givens

d1 = 1.5

d2 = ?

m1 = 50 kg

m2 = 30 kg

The lighter child will have to sit further away from the pivot to make the two conditions equal.

Formula

d1*m1 = d2*m2

1.5*50 = d2 * 30

75 = 30 * d2

75/30 = d2

d2 = 2.5

Remark

Notice that the distance is longer for the lighter child. The fact that these are masses and not forces does not matter, but you should take note of it. There is a difference between masses and forces. See the fishing pole problem.

Answer to the multiple Choice question. No motion on this kind of problem means equal moments. The answer is D

Problem 2

1) The wheels are further apart making B more stable. The wider the distance the wheels are apart, the harder it would be to tip the concrete mixer over

2) The center of gravity is lower. The higher the force is the more chance you have of exerting an external force to tip the mixer over.

7 0
3 years ago
An astronaut has a momentum of 280 kg and travels 10 m/s. what is the mass of the astronaut?
Kamila [148]

Answer:

The answer is

<h2>28 kg</h2>

Explanation:

The mass of an object given it's momentum and velocity / speed can be found by using the formula

m =  \frac{p}{v}  \\

where

m is the mass

p is the momentum

v is the speed or velocity

From the question

p = 280 kg/ms

v = 10 m/s

The mass of the object is

m =  \frac{280}{10}  = 28 \\

We have the final answer as

<h3>28 kg</h3>

Hope this helps you

3 0
3 years ago
A proton and an electron are moving in the +x direction in a magnetic field in the +z
Aleksandr [31]

Answer:

Explanation:

Force on a moving charge is given by the following relation

F = q ( v x B )

for proton

q = e  ,   v = vi  , B = Bk

F = e ( vi x Bk )

= Bev - j

= - Bevj

The direction of force is along negative of y axis or -y - axis.

for electron

q = - e  ,   v = vi  , B = Bk

F = - e ( vi x Bk )

= - Bev - j

=  Bevj

The direction of force is along positive  of y axis or + y - axis.

5 0
3 years ago
(HELP!! 10pts) a train travels 75km in 1hr, and then 68km in 2hrs. what is its average speed?
blondinia [14]
Average speed = total distance travelled ÷ total time taken

AS = (75km + 68km) ÷ (1hr + 2hr)

As = 143km ÷ 3hr

AS = 47.66667 km/hr

AS = 47.7 km/hr (3sf)
8 0
3 years ago
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