HEY GUYS IS THIS TRUE OR FALSE????????
2 answers:
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Answer:
2.83 m/s
Explanation:
Given:
Mass of the cart (m) = 20.0 kg
Initial velocity of the cart (u) = 0 m/s
Final velocity (v) = ? m/s
Displacement of the cart (S) = 8.0 m
Horizontal force acting on the cart (F) = 10.0 N
Surface is frictionless. So, only horizontal force is the force acting on the cart.
Now, as per work-energy theorem, the work done by the net force acting on a body is equal to the change in the kinetic energy of the body.
Here, the work done by the horizontal force is given as:
The change in kinetic energy is given as:
Now, from work-energy theorem:
Therefore, the speed of the cart when it has been pushed 8.0 m is 2.83 m/s.
Answer:
A. when the mass has a displacement of zero
Explanation:
The velocity of a mass on a spring can be calculated by using the law of conservation of energy. In fact, the total energy of the mass-spring system is equal to the sum of the elastic potential energy (U) of the spring and the kinetic energy (K) of the mass:
where
k is the spring constant
x is the displacement of the mass with respect to the equilibrium position of the spring
m is the mass
v is the velocity of the mass
Since the total energy E must remain constant, we can notice the following:
- When the displacement is zero (x=0), the velocity must be maximum, because U=0 so K is maximum
- When the displacement is maximum, the velocity must be minimum (zero), because U is maximum and K=0
Based on these observations, we can conclude that the velocity of the mass is at its maximum value when the displacement is zero, so the correct option is A.