Answer:
C) unbalanced
Explanation:
Equal forces acting in opposite directions are called balanced forces. Balanced forces acting on an object will not change the object's motion. When you add equal forces in opposite direction, the net force is zero.
Answer:
Eleven seconds.
Explanation:
Two keys are needed to solve this problem. First, the conservation of momentum: allowing you to calculate the cart's speed after the elephant jumped onto it. It holds that:

So, once loaded with an elephant, the cart was moving with a speed of 4.29m/s.
The second key is the kinematic equation for accelerated motion. There is one force acting on the cart, namely friction. The friction acts in the opposite direction to the horizontal direction of the velocity v0, its magnitude and the corresponding deceleration are:

The kinematic equation describing the decelerated motion is:

It takes 11 seconds for the comical elephant-cart system to come to a halt.
Da Vinci was fascinated by how timepieces operate. Based on one of his sketches, it uses the laws of motion and a vertical "flying" pendulum escapement to keep accurate time.
The pendulum's weights, in a bucket suspended from a crane-style arm, act as the clock's power source. The weights propel the pendulum from vertical post to vertical post. As it "flies" it turns precision gears, which in turn keep time. To speed up or slow the clock, adjust the weight-balance of the pendulum by adding or removing weights.