Answer:
a. 4.5secs
Explanation:
From the question, the equation describing the height is given by

at the point when the rock hit the ground, the height,h will be zero.
Hence we can have

hence the rock will hit the ground in 4.5secs
Answer:
X=m*g/K
Explanation:
Since the elastic force of the spring is balancing the force of gravity:
Fe = m*g
Now, on the spring by Hook's law, the magnitude of the elastic force will be:
Fe = K*X where K is the elastic constant of the spring and X is the distance the spring is strectches measured from its original lenght to its current length.
Replacing this value:
K*X = m*g Solving for X:
X = m*g/K This value is directly proportional to the object's weight and inversely proportional to the spring's constant.
Vector trigonometry can be used for this problem. Since the horizontal component is 12 meters per second, this is technically the hypotenuse (actual initial velocity) multiplied to cosine of 40 degrees. Therefore, to find the hypotenuse, we must divide 12 by cosine 40degrees. cos(40)= 0.766, and 12/0.766 = approximately 15.664, therefore our answer is (3) 15.7 m/s
Answer:
The polarity of electromagnet also gets reversed when the direction of current is reversed. The current flows from negative terminal to positive terminal in an electromagnet due to the flow of electrons so polarity is also established in the electromagnet. As, the current direction is reversed, the polarity of magnet also gets reversed because the polarity of magnet depends on the direction of the current.
Answer:
Explanation: velocity 4m/s is found by: 7-3 so if you want to find Velocity for 10kg You need to do 10-3
The answer is 7m/s
I hope u have understood it