Answer:
3. 9600m/s
4. 2.5m/s
Explanation:
To find the final velocity of the object which accelerates at 40m/s/s for four minutes, we first need to convert the 4 minutes to seconds. There are 60 seconds in a minute so 4 minutes is equal to 4x60 = 240 seconds.
To calculate the final velocity we just multiply the acceleration rate by the time, so 40x240=9,600 m/s
The final velocity of the object would be 9600m/s.
If an object's final velocity was 115m/s after 45 seconds then we need to find out how much it accelerated in that 45 seconds to find the starting velocity. 45x2.5=112.5 It increased in speed by 112.5m/s over 45 seconds, so its initial speed was 112.5m/s slower than its final speed. 115-112.5=2.5, the object's starting velocity was 2.5m/s.
Hope this helped!
Answer:
q_poly = 14.55 KJ/kg
Explanation:
Given:
Initial State:
P_i = 550 KPa
T_i = 400 K
Final State:
T_f = 350 K
Constants:
R = 0.189 KJ/kgK
k = 1.289 = c_p / c_v
n = 1.2 (poly-tropic index)
Find:
Determine the heat transfer per kg in the process.
Solution:
-The heat transfer per kg of poly-tropic process is given by the expression:
q_poly = w_poly*(k - n)/(k-1)
- Evaluate w_poly:
w_poly = R*(T_f - T_i)/(1-n)
w_poly = 0.189*(350 - 400)/(1-1.2)
w_poly = 47.25 KJ/kg
-Hence,
q_poly = 47.25*(1.289 - 1.2)/(1.289-1)
q_poly = 14.55 KJ/kg
Answer:
A. 20 N
Explanation:
weight of book is 2×10=20N .....
The number and units. An example would be 3cm or 4kg.
