World-class sprinters can accelerate out of the starting blocks with an acceleration that is nearly horizontal and has magnitude 15m/s^2 .

Part a)How much horizontal force F must a sprinter of mass 60kg exert on the starting blocks to produce this acceleration? express your answer in newtons
Part b)
Which body exerts the force that propels the sprinter, the blocks or the sprinter?

question # 2: net force of 225 N accelerates a bike and rider at 2.65m/s^2. What is the mass of the bike and rider together ?

Thank you .

Part a) To calculate the force (F) exerted by the sprinter on the starting blocks, we can use Newton's second law of motion:

F = ma

Where F is the force, m is the mass, and a is the acceleration.

Given:
- Mass of the sprinter (m) = 60 kg
- Acceleration (a) = 15 m/s^2

Substituting these values into the equation, we can calculate the force:

F = (60 kg) * (15 m/s^2)
F = 900 kg⋅m/s^2

Therefore, the horizontal force that the sprinter must exert on the starting blocks is 900 Newtons.

Part b) According to Newton's third law of motion, for every action, there is an equal and opposite reaction. So, if the sprinter exerts a force on the starting blocks, the starting blocks will exert an equal and opposite force on the sprinter.

Therefore, the force that propels the sprinter forward comes from the starting blocks.

Part a) To determine the horizontal force F exerted by the sprinter, we can use Newton's second law of motion, which states that the net force acting on an object is equal to the product of its mass and acceleration. Mathematically, it can be written as:

F = m * a

Where F is the force, m is the mass, and a is the acceleration.

In this case, the sprinter has a mass of 60 kg and an acceleration of 15 m/s^2. Plugging these values into the equation, we get:

F = 60 kg * 15 m/s^2
F = 900 N

Therefore, the sprinter needs to exert a horizontal force of 900 Newtons.

Part b) The force that propels the sprinter is exerted by the blocks. This is because, according to Newton's third law of motion, every action has an equal and opposite reaction. As the sprinter pushes against the blocks with a force F, the blocks exert an equal and opposite force on the sprinter, propelling them forward.

Question #2: To find the mass of the bike and rider together, we can again use Newton's second law of motion. The formula remains the same:

F = m * a

We are given a net force of 225 N and an acceleration of 2.65 m/s^2. Plugging these values into the equation, we get:

225 N = m * 2.65 m/s^2

To solve for the mass (m), we need to rearrange the equation:

m = 225 N / 2.65 m/s^2
m ≈ 84.91 kg

Therefore, the mass of the bike and rider together is approximately 84.91 kilograms.

A : F=ma

B : m= F/a