# Physics - Momentum/Direction of RBC and leukocyte after collision

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#### Feedmecupcakes

##### Full Member
2+ Year Member

I'm struggling with this question:
A red blood cell and a leukocyte collide from converging arteries. The RBC, being lighter, ricochets obliquely off the vein's longitudinal axis while continuing to move to the right. What is the direction of the RBC's acceleration?
The answers are just arrows so I'll describe as if they were sitting on a clock.
A. Straight up (12oo)
B. Up to the left (1000)
C. Right (300)
D. Up to the right (2oo)

I said D since that was what I pictured, but the answer is A since that is the "direction of acceleration".
But isn't acceleration diagonally right? I don't understand the explanation.
Im so bad at physics QQQQQQ

#### memory tcells

##### Full Member
First off, I feel there is a picture missing from this question but I'll give this a shot.

The important sentence here is:
"The RBC, being lighter, ricochets obliquely off the vein's longitudinal axis while continuing to move to the right."

The question states that it continues to move to the right ( Now based on how its worded, I'm assuming it means that it continues to move at the same horizaontal velocity) so therefore acceleration=0 horizontally. Without numbers, there is no way to know how much in that direction. But there is also a vertical component, the only way it can move vertically away from its original vertical direction is if the acceleration is opposite of its original direction. Again, there is no numerical value given in the question but the answers give numerical values. However, in this case it doesn't matter because there is only one answer choice in the vertical axis. Answer is A.

#### Feedmecupcakes

##### Full Member
2+ Year Member
First off, I feel there is a picture missing from this question but I'll give this a shot.

The important sentence here is:
"The RBC, being lighter, ricochets obliquely off the vein's longitudinal axis while continuing to move to the right."

The question states that it continues to move to the right ( Now based on how its worded, I'm assuming it means that it continues to move at the same horizaontal velocity) so therefore acceleration=0 horizontally. Without numbers, there is no way to know how much in that direction. But there is also a vertical component, the only way it can move vertically away from its original vertical direction is if the acceleration is opposite of its original direction. Again, there is no numerical value given in the question but the answers give numerical values. However, in this case it doesn't matter because there is only one answer choice in the vertical axis. Answer is A.