kinematic

1. Doubts on the sign of acceleration

What should I do? Because I have two possibilities. I have $0=5+at$ so $-5/t =a$. But then I can also say that the acceleration is a negative because it is stopping, so I can write it like $0=5-kt$ and then $5/t =k$

21. Relationship between ln k and 1/t using different formula

Hi, I'm currently taking Chemistry 101 and came across this equation that seems to contradict what I've learned before. I don't know the name of it, but here is the equation and its implication. Now another equation we have learned is the Arrhenius equation, which is as follows: If I...
22. Electrical Help finding appropriate equipment

I would like to measure time period of very short periods of electricity flow in the range of micro seconds or even smaller;can someone tell me me a device that can help me do this?
23. B Laws of motion while climbing a Rope

I'm a little confused with the application of laws of motion on a man climbing a rope. Suppose a man of mass Mg is climbing a rope with an acceleration a. Rope is massless. Now if look through the frame of the piece of rope held by the man, there is a force Mg downward by man, ma downward...
24. Setting equations equal to each other

1. Homework Statement Two cars are facing each other on a long straight airport runway. They are initially separated by a distance of 1 km. Car A begins to accelerate towards the other car at a uniform 0.5 ms^-2. Ten seconds later car B begins to move towards the other car with a uniform...
25. An electron & a proton are each placed in an electric field

1. Homework Statement An electron and a proton are each placed at rest in an electric ﬁeld of 687 N/C. What is the velocity of the electron 56.5 ns after being released? Consider the direction parallel to the ﬁeld to be positive. The fundamental charge is 1.602×10−19 C, the mass of a proton is...
26. I'm stuck! This is a combination of dynamics and free fall

1. Homework Statement A flat cushion of mass m is released from rest at the corner of the roof of a building, at height h. A wind blowing along the side of the building exerts a constant horizontal force of magnitude F on the cushion as it drops as shown in the figure below. The air exerts no...
27. I have a hard time with kinematics involving inclined planes

1. Homework Statement Two blocks of mass m1 = 3.00 kg and m2 = 6.00 kg are connected by a massless string that passes over a frictionless pulley (see the figure below). The inclines are frictionless. Image - https://www.webassign.net/serpse9/5-p-049.gif The inclined plane is shaped like a...
28. Raindrop free falling -- calculate the velocity and time

1. Homework Statement Raindrops fall from a broken gutter at 1.0 s intervals to the ground , 19.6 m below Neglecting air resistance and taking g as 9.81 calculate the time for each drop to reach the ground velocity of the drops as they reach the ground speed of drop at the height of 14.7 m...
29. Kinematics of a Car Crash

1. Homework Statement "Based on the following data, determine if the driver who crashed was driving over the speed limit" The relevant data given is: -A 2002 Volvo t-bones a truck in an alley with a speed limit of 20km/h -An eyewitness heard tires screech, then a loud bang, and also said...
30. Kinematics within a simulation

1. Homework Statement I'm simulating a warehouse (in Unity) where forklifts and other vehicles transport stuff from point A to point B. The routes are modeled as a graph with vertices and edges. Every transport is saved as a task in a backend system with the relevant data such as starting time...