Static friction is the friction that exists between two surfaces in contact. For a static body, the applied force (Fm) used to move the body is always equal to the frictional force(Ff) since frictional force is a force of opposition that tends to oppose the moving force acting on a static body.
According to the question, if Adam and Natalie push on a cart using 150N force, then the force of friction on the cart will be equal and opposite to the applied force and will also be equal to 150N
The relationship between medium temperature and speed of sound is a direct relationship: when one factor increases, the other increases as is shown in graph B. The British would choose the the time of day which would give the lowest speed of sound, because this would be easiest to break. Graph B shows that the lowest speed of sound would occur with the lowest air temperature - in the morning.
