# Solving SAT Physics: Momentum of Block Starting from Rest at 5s

• spyroarcher
In summary, the question is asking for the momentum of a block starting from rest after 5 seconds, and the answer is 10 kg m/s. The equations p=mv, F=ma, and v=at are relevant to solving this question.
spyroarcher

## Homework Statement

If the block starts from rest, its momentum at 5 seconds is...

p=mv
F=ma
v=at

## The Attempt at a Solution

When I thought about it, I was thinking about p=mv, and I had to substitute v to get a desirable answer. So I did p=m(at). However I only know the time, and I know the answer is 10 kg m/s, but I am not sure how to do it. Thanks in advance.

"If the block starts from rest, its momentum at 5 seconds is..."

Is that the full question? If so, there is no answer.

Yes that is the full question, if it is impossible, how would the book get 10?
It also said p=F(change in T) for the answer

Sure, F=dp/dt, so ∆p=∫Fdt. If you have a constant force of 2N acting on the particle you will get ∆p=F∆t=2*5=10 kgm/s, but I don't see anything about that.

I would approach this problem by first understanding the concept of momentum and how it is related to the mass and velocity of an object. The equation p=mv tells us that the momentum of an object is equal to its mass multiplied by its velocity. In this case, the block is starting from rest, which means its initial velocity is 0 m/s. We also know that the block has a mass of 10 kg.

Using the equation v=at, we can calculate the final velocity of the block at 5 seconds. Since the block is starting from rest, its initial velocity is 0 m/s and the acceleration is constant at all times, we can simply use the equation v=at to find the final velocity.

v=at
v=(5s)(a)
v=5a

Now, we can substitute this value for velocity into the equation p=mv.

p=mv
p=(10kg)(5a)
p=50a

Finally, to find the momentum at 5 seconds, we need to know the value of acceleration. This can be found by using the equation F=ma, where F is the force acting on the block. If we assume that there is a constant force acting on the block, we can find the acceleration by dividing the force by the mass.

F=ma
a=F/m

Substituting this value for acceleration into our equation for momentum, we get:

p=50(F/m)

Since we know that the mass of the block is 10 kg, we can simplify this equation to:

p=5F

This tells us that the momentum of the block at 5 seconds is directly proportional to the force acting on it. Therefore, if we know the force acting on the block, we can easily calculate its momentum at 5 seconds.

In summary, to solve this problem, we used the equations p=mv, v=at, and F=ma to find the momentum of the block at 5 seconds. By understanding the concepts of momentum, mass, velocity, acceleration, and force, we were able to use these equations to arrive at a solution.

## What is momentum in physics?

Momentum is a fundamental concept in physics that describes the quantity of motion an object has. It is defined as the product of an object's mass and its velocity.

## How do I calculate the momentum of a block starting from rest at 5 seconds?

In order to calculate the momentum of a block starting from rest at 5 seconds, you will need to know the mass of the block and its velocity at 5 seconds. You can then use the equation p = mv to calculate the momentum, where p is momentum, m is mass, and v is velocity.

## What is the difference between momentum and velocity?

Momentum and velocity are related concepts, but they are not the same thing. Velocity is a vector quantity that describes the speed and direction of an object's motion, while momentum is a vector quantity that describes the quantity of motion an object has.

## Can momentum be negative?

Yes, momentum can be negative. Since momentum is a vector quantity, it has both magnitude and direction. If an object is moving in the opposite direction of its initial velocity, its momentum will be negative.

## Why is the conservation of momentum important in physics?

The law of conservation of momentum states that the total momentum of a closed system remains constant. This means that in any interaction or collision between objects, the total momentum before and after the interaction will be the same. This principle is important in understanding and predicting the motion of objects in various physical systems.

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