Pitch is directly related to the frequency of the sound. In this item, we are given that the frequency of the sound is higher compared to those which are audible to the human being's ears. The pitch therefore of the dog's whistle is high.
On the other hand, the frequency and the wavelength of a certain wave are inversely proportional. This means that the high frequency wave will have a short wavelength.
Hence, the answer to this item would have to be "high pitch with a short wavelength"
The answer to this item is the second option.
Larger mass creates a stronger pull
Answer:
False statement = There must be a non-zero net force acting on the object.
Explanation:
An object is moving at a constant speed along a straight line. If the speed is constant then its velocity must be constant. We know that the rate of change of velocity is called acceleration of the object i.e.

a = 0
⇒ The acceleration of the object is zero.
The product of force and acceleration gives the magnitude of force acting on the object i.e.
F = m a = 0
⇒ The net force acting on the object must be zero.
So, the option (a) is not true. This is because the force acting on the object is zero. First option contradicts the fact.
The cart experiences a frictional force which is directly proportional to its weight. This means that there must be a force applied on the car to balance the forces on the car to produce a net force of 0.
This is in accordance to Newton's first law which states that an object at rest will remain at rest and an object in motion will remain in motion unless an external force acts on it. The force must be a resultant force.
Therefore, the force needed increases with the total weight of the cart as well as with the added mass in a linear manner.
Answer:
The magnetic field strength inside the solenoid is
.
Explanation:
Given that,
Radius = 2.0 mm
Length = 5.0 cm
Current = 2.0 A
Number of turns = 100
(a). We need to calculate the magnetic field strength inside the solenoid
Using formula of the magnetic field strength
Using Ampere's Law

Where, N = Number of turns
I = current
l = length
Put the value into the formula


(b). We draw the diagram
Hence, The magnetic field strength inside the solenoid is
.