Answer:
Explanation:
Consider the initial position of the frog (20 m above ground) as the reference position. All measurements are positive measured upward.
Therefore,
u = 10 m/s, initial upward velocity.
H = - 20 m, position of the ground.
g = 9.8 m/s², acceleration due to gravity.
Part (a)
When the frog reaches a maximum height of h from the reference position, its velocity is zero. Therefore
u² - 2gh = 0
h = u²/(2g) = 10²/(2*9.8) = 5.102 m
At maximum height, the frog will be 20 + 5.102 = 25.102 m above ground.
Answer: 25.1 m above ground
Part (b)
Let v = the velocity when the frog hits the ground. Then
v² = u² - 2gH
v² = 10² - 2*9.8*(-20) = 492
v = 22.18 m/s
Answer: The frog hits the ground with a velocity of 22.2 m/s
Answer:

Explanation:
Let suppose that centrifuge is rotating at constant angular speed, which means that resultant acceleration is equal to radial acceleration at given radius, whose formula is:

Where:
- Angular speed, measured in radians per second.
- Radius of rotation, measured in meters.
The angular speed is first determined:

Where
is the angular speed, measured in revolutions per minute.
If
, the angular speed measured in radians per second is:


Now, if
and
, the resultant acceleration is then:


If gravitational acceleration is equal to 9.807 meters per square second, then the radial acceleration is equivalent to 1006.382 times the gravitational acceleration. That is:

Answer:
Acceleration = 0.9144 m/s^2
Explanation:
Initial speed = 45 ft/s
Final speed = 60 ft/s
Time = 5 sec
Acceleration = a = (v-u) / t
= 60-45 / 5
= 0.9144 m/s^2
Answer:
N = 648.55[N]
Explanation:
To solve this problem we must use Newton's second law which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
∑F = m*a
where:
∑F = Forces applied [N]
m = mass = 73.2 [kg]
a = acceleration = 0.950 [m/s²]
Let's assume the direction of the upward forces as positive, just as if the movement of the box is upward the acceleration will be positive.
By performing a summation of forces on the vertical axis we obtain all the required forces and other magnitudes to be determined.

where:
g = gravity acceleration = 9.81 [m/s²]
N = normal force (or weight) measured by the scale = 83.4 [N]
Now replacing:
![-(73.2*9.81)+N=-73.2*0.950\\-718.092+N=-69.54\\N = -69.54+718.092\\N = 648.55[N]](https://tex.z-dn.net/?f=-%2873.2%2A9.81%29%2BN%3D-73.2%2A0.950%5C%5C-718.092%2BN%3D-69.54%5C%5CN%20%3D%20-69.54%2B718.092%5C%5CN%20%3D%20648.55%5BN%5D)
The acceleration has a negative sign, this means that the elevator is descending at that very moment.
Solids
Hope this helped:)