Speed, velocity and accelaration

AI Thread Summary
The discussion addresses two physics problems involving speed, velocity, and acceleration. For the first question, the average speed of the boat is calculated as 6.7 m/s, while the average velocity is determined to be 4.7 m/s in the southeast direction. The second question involves a car accelerating from 10 m/s to 25 m/s over 5 seconds, yielding an acceleration of 3 m/s². The calculations provided demonstrate the application of basic physics formulas for speed, velocity, and acceleration. This thread effectively clarifies these concepts through practical examples.
billytonydavies
Messages
3
Reaction score
0
Just need some help with the following questions which are probably very easy to you guys. Here are the 2 questions I need help with.

1). A boat sails 150m due south and 150m due east. This takes a total time of 45s. Calculate (i). the boat's average speed and (ii) the boats average velocity.

2). A car traveling at 10 ms -1 due north speeds up uniformly to a velocity of 25 ms-1 in 5 s. Calculate the acceleration of the car during these 5 seconds. Let the direction of the motion of the car, due north, be taken as the positive (+) direction.

Thanks in advance.

Billy. Can email me at: annaporcel@talk21.com
 
Physics news on Phys.org
1) Average speed = Total Distance/Total Time = 300m/45s = 6.7m/s
Average velocity = Total Displacement/Total Time = (150m[south] + 150m[east])/45s
= 150\sqrt{2}m[south-east]/45s = 4.7m/s[south-east]

2) a = (v2 - v1)/t = (25 - 10)/5 = 3 m/s -2
 
Thanks

Thanks very much for your help. Much appreciated.
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »
Thread 'Minimum mass of a block'

Thread 'Minimum mass of a block'

Here we know that if block B is going to move up or just be at the verge of moving up ##Mg \sin \theta ## will act downwards and maximum static friction will act downwards ## \mu Mg \cos \theta ## Now what im confused by is how will we know " how quickly" block B reaches its maximum static friction value without any numbers, the suggested solution says that when block A is at its maximum extension, then block B will start to move up but with a certain set of values couldn't block A reach...
View full post »

Similar threads

Calculate the Acceleration of this Car
Replies
7
Views
976
Calculating the time to cross a river
Replies
4
Views
3K
Adding Vectors to Find Velocity
Replies
16
Views
3K
Help with question on motion: Avoiding a rear-end collision
Replies
6
Views
3K
Determine magnitude of change in velocity and direction
Replies
2
Views
2K
Calculate Distance Traveled: Instantaneous vs. Average Velocity
Replies
5
Views
2K
What is the speed of the boat relative to the water?
Replies
6
Views
4K
Physics magnitude and direction?
Replies
4
Views
2K
Homework help with interpreting SUTAV questions
Replies
5
Views
1K
Why Does Car A Appear to Travel Southeast from Car B's Perspective?
Replies
4
Views
4K

Hot Threads

Recent Insights

Back
Top