Momentum impulse physics question, HELP

In summary, a 4.0-kg block initially slides at a constant speed of 5.0 m/s on a frictionless surface. Two seconds later, a time-dependent force is applied to the block and then removed after eight seconds. The magnitude of the total impulse of the force acting on the block is 42N. At t = 10 seconds, the approximate speed of the block is 7.5 m/s. To solve this problem, the equations p=mv and KE=1/2mv^2 were used, along with the equation p=int F(t)dt, which represents the change in momentum as the area under the force-time graph.
  • #1
enchantress95
1
0
Momentum impulse physics question, HELP ASAP please!

Homework Statement


A 4.0-kg block slides along a frictionless surface with a constant speed of 5.0 m/s as shown. Two seconds after it
begins sliding, a horizontal, time-dependent force is applied to the mass. The force is removed eight seconds later. The
graph shows how the force on the block varies with time.
• What is the magnitude of the total impulse of the force acting on the block?
• What, approximately, is the speed of the block at t = 10 seconds?



Homework Equations



p= mv
K.E= 1/2*m*v^2

The Attempt at a Solution


p= mv = 20kg*m/s
K.E= 1/2*m*v^2 = 50 J

I was solving this past paper and the answer is 42N but idk how to get tht :s any help wud be appreciated, thanks!
 
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  • #2
Welcome to PF;
Please show us your working and how you have been thinking about the problem so far.
That is the best and fastest way to get the help you need.

You are missing an equation - ##p=\int F(t)\; dt##
... which is to say: the change in momentum is the area under the force-time graph.
... what is "specific impulse"?
 

What is momentum?

Momentum is a measure of an object's motion and is defined as the product of its mass and velocity. It is a vector quantity, meaning it has both magnitude and direction. The SI unit for momentum is kilogram-meters per second (kg*m/s).

What is impulse?

Impulse is the change in momentum of an object and is equal to the force applied to the object multiplied by the time it is applied. It is also a vector quantity and has the same units as momentum, kg*m/s.

How are momentum and impulse related?

Momentum and impulse are both measures of an object's motion and are directly related. The impulse acting on an object is equal to the change in momentum of that object. This is represented by the equation Impulse = Change in Momentum.

How is momentum conserved in a system?

Momentum is conserved in a system when there are no external forces acting on the system. This means that the total momentum before and after a collision or interaction within the system remains the same. This is known as the law of conservation of momentum.

How is the conservation of momentum applied in real life?

The conservation of momentum is applied in many real-life situations, such as in sports, transportation, and space exploration. In sports, for example, a basketball player can increase their momentum by taking a running start before a jump. In transportation, the momentum of a moving vehicle must be considered to safely make turns and stop. In space exploration, the conservation of momentum is used to propel spacecraft by using the momentum of ejected gases.

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