Answer:
negative acceleration of 4m/s²
Step-by-step explanation:
Given parameters: 
Initial velocity = 66m/s
Final velocity = 26m/s 
Time taken = 10s 
Unknown: 
Description of the acceleration = ? 
Solution: 
Acceleration is the rate of change of velocity with time. 
It is mathematically expressed as; 
 acceleration = 
 
 
v is the final velocity 
u is the initial velocity
t is the time taken 
 Now insert the parameters and solve; 
 Acceleration = 
 = -4m/s²
 = -4m/s² 
So, we see a negative acceleration of 4m/s²