Answer:
12.7m/s
Explanation:
Given parameters:
Mass of the diver = 77kg
Height = 8.18m
Unknown:
Speed of the diver before hitting the water = ?
Solution:
The speed of the diver before hitting the water is the final velocity.
To solve this problem, we use the expression below;
v² = u² + 2gH
v is the final velocity
u is the initial velocity
g is the acceleration due to gravity
H is the height
Now insert the parameters and solve;
v² = 0² + 2 x 9.8 x 8.18
v² = 160.328
v = 12.7m/s
Answer:
Final Speed of Dwayne 'The Rock' Johnson = 15.812 m/s
Explanation:
Let's start out with finding the force acting downwards because of the mass of 'The Rock':
Dwayne 'The Rock' Johnson: 118kg x 9.81m/s = 1157.58 N
Now the problem also states that the kinetic friction of the desk in this problem is 370 N
Since the pulley is smooth, the weight of Dwayne Johnson being transferred fully, and pulls the desk with a force of 1157.58 N. The frictional force of the desk is resisting this motion by a force of 370 N. Subtracting both forces we get the resultant force on the desk to be: 1157.58 - 370 = 787.58 N
Now lets use F = ma to calculate for the acceleration of the desk:
787.58 = 63 x acceleration
acceleration = 12.501 m/s
Finally, we can use the motion equation:

here u = 0 m/s (since initial speed of the desk is 0)
a = 12.501 m/s
and s = 10 m
Solving this we get:


Since the desk and Mr. Dwayne Johnson are connected by a taught rope, they are travelling at the same speed. Thus, Dwayne also travels at 15.812 m/s when the desk reaches the window.
A plane mirror doesn't change the apparent size or shape of things.
-- If the meter stick is held parallel to the mirror, or is lying on the mirror,
then its image in the mirror is 1 meter long.
-- If the meter stick is held perpendicular to the mirror, or is standing on
the mirror, or pointing directly at it, then its image in the mirror has no length.
Given:
mass = 6 kg
velocity = 4 m/s
To find:
Kinetic energy of the cart = ?
Formula used:
Kinetic energy = 
Where m = mass of the cart
v = velocity with which the cart is moving
Solution:
Kinetic energy of the moving cart is given by,
Kinetic energy = 
Where m = mass of the cart
v = velocity with which the cart is moving
Kinetic energy =
Kinetic energy = 48 Joule
Thus, the kinetic energy of the moving cart is 48 Joule.