No force is required to lift that balloon. In fact, force is required to hold it down, and if you let go, it's up, up, and away.
Since the balloon's density is less than the density of the air around it, it's lighter than the air it displaces, there is a net upward buoyant force acting on it, and it floats up !
C, they didn't know any better
Because the act of braking is an example of negative acceleration.
Example: if the rate of braking was say 2 meters per second^2, and the starting velocity was 10 m/s, it would take 5 seconds to come to a stop(during those 5 seconds you would still be moving).
Answer:
7.39 m/s
Explanation:
Applying
K.E = 1/2mv²..................... Equation 1
Where K.E = Kinetic Energy, m = mass of the ball, v = velocity of the ball.
Make v the subject of the equation
v = √(2K.E/m)................. Euqation 2
From the question,
Given: K.E = 30 J, m = 1.1kg
Substitute these values into equation 2
v = √(2×30/1.1)
v = √54.54
v = 7.39 m/s
