Motion in 2 dimension (undergrad level)

I don't know how to proceedIn summary, the problem involves a hero throwing a grenade from a car traveling at 79.0 km/h to an enemy's car traveling at 116 km/h. The initial velocity of the grenade, relative to the hero, is at an angle of 45 degrees above the horizontal. The cars are both moving in the same direction on a level road and air resistance can be ignored. The question asks for the magnitude of the initial velocity of the grenade. The attempted solution involved subtracting the relative velocity of the grenade, 37 km/h, but further steps are unclear.
  • #1
wenkang
2
0

Homework Statement



In an action-adventure film, the hero is supposed to throw a grenade from his car, which is going 79.0 km/h , to his enemy's car, which is going 116 km/h . The enemy's car is 16.1m in front of the hero's when he let's go of the grenade. If the hero throws the grenade so its initial velocity relative to him is at an angle of 45 above the horizontal, what should the magnitude of the initial velocity be? The cars are both traveling in the same direction on a level road. You can ignore air resistance.


Homework Equations





The Attempt at a Solution

 
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  • #2
I will gladly assist you, however can you please show an attempt as per PF guidelines.

Jared
 
  • #3
I am totally stucked at this question, I tried to minus 37 km/h as relative velocity of the bomb but it doesn't work
 

FAQ: Motion in 2 dimension (undergrad level)

1. What is the difference between distance and displacement?

Distance refers to the total amount of ground covered by an object, while displacement is the shortest distance between the initial and final position of an object. Distance is a scalar quantity, while displacement is a vector quantity.

2. How is velocity different from speed?

Velocity is a vector quantity that describes the rate of change of an object's displacement, while speed is a scalar quantity that describes the rate of change of an object's distance. Velocity includes both the magnitude and direction of an object's motion, while speed only considers the magnitude.

3. What is the difference between average velocity and instantaneous velocity?

Average velocity is the total displacement of an object divided by the total time taken, while instantaneous velocity is the velocity of an object at a specific moment in time. Average velocity provides an overall picture of an object's motion, while instantaneous velocity provides a more detailed view at a specific point in time.

4. How do you calculate acceleration in 2D motion?

In 2D motion, acceleration can be calculated by dividing the change in an object's velocity by the total time taken. This can be represented by the formula a = (vf - vi)/t, where a is acceleration, vf is the final velocity, vi is the initial velocity, and t is time.

5. How does the angle of a projectile's initial velocity affect its motion?

The angle of a projectile's initial velocity affects its motion by determining the direction of its path. A higher angle will result in a higher peak height and a longer time in the air, while a lower angle will result in a shorter distance but a longer time in the air. The optimal angle for maximum distance is 45 degrees.

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