Valleys are one of the most common landforms on the Earth and they are formed through erosion or the gradual wearing down of the land by wind and water. In river valleys for example, the river acts as an erosional agent by grinding down the rock or soil and creating a valley
 
        
             
        
        
        
If its accelerating it will increase velocity in the direction of the acceleration which is perpendicular to the velocity.
        
             
        
        
        
Answer:
C. A rubber rod and a glass rod charged this way have opposite charges on them.
Explanation:
When a rubber rod is rubbed against cat fur, it acquires a negative charge, it becomes negatively charged.
When you then try to bring two rubber rod's together, they repel because like charges repel.
Meanwhile, when you rub a glass rod against silk, it loses electrons to the silk material and becomes positively charged.
When you bring two positively charged glass rod's together, they repel, because like charges repel. 
However, when you bring the rubber rod and a glass rod together, the attract each other because unlike/opposite charges attract. 
 
        
             
        
        
        
Answer:
T = 25 N
Explanation:
The question says that "A 25 n block is suspended by a wire from the ceiling vitamin the tension that appears in the wire
?"
Weight of the block, W = 25 N
Weight of a body acts in downward direction and tension acts in upward direction. It would mean that,
Tension = weight of the block
T = mg
T = 25 N
Hence, the tension in the wire is 25 N.
 
        
             
        
        
        
Answer:
Explanation:
a )
While breaking initial velocity u = 62.5 mph 
= 62.5 x 1760 x 3 / (60 x 60 )  ft /s 
= 91.66 ft / s 
distance trvelled s = 150 ft 
v² = u² - 2as 
0 = 91.66²  - 2 a x 150 
a = - 28 ft / s²
b ) While accelerating initial velocity u = 0 
distance travelled s = .24 mi 
time = 19.3 s 
s = ut + 1/2 at²
s is distance travelled in time t with acceleration a , 
.24 = 0 + 1/2 a x 19.3²
a = .001288 mi/s²
= 2.06 m /s²
c )
If distance travelled s = .25 mi 
final velocity v = ? a = .001288 mi / s²
v² = u² + 2as 
= 0 + 2 x .001288 x .25 
= .000644
v = .025 mi / s 
= .0025 x 60 x 60 mi / h 
= 91.35 mph . 
d ) initial velocity u = 59 mph 
= 86.53 ft / s 
final velocity = 0 
acceleration = - 28 ft /s²
v = u - at 
0 = 86.53 - 28 t
t = 3 sec approx .