When the forces acting on a body are balanced, their effect
\on the body's motion is the same as if no forces at all are
acting on it, and its velocity can't change. It continues moving
in a straight line at constant speed (which may be zero).
Answer:
20 J
Explanation:
Kinetic energy is given as half of the product of mass and the square of velocity of an object:
KE = 
where m = mass = 40 kg
v = velocity = 1 m/s
Hence, Mary's kinetic energy is:
KE = 
KE = 20 * 1 = 20 J
She has a kinetic energy of 20 J.
The distance between two consecutive points in a wave is called the wavelength.
The acceleration exerted by the object of mass 10 kg is 
Answer: Option A
<u>Explanation:</u>
According to Newton’s second law of motion, any external force acting on a body will be directly proportional to the mass of the body as well as acceleration exerted by the body. So, the net external force acting on any object will be equal to the product of mass of the object with acceleration exerted by the object. Thus,

So,

As the force acting on the object is stated as 10 N and the mass of the object is given as 10 kg, then the acceleration will be

So, the acceleration exerted by the object of mass 10 kg is 